Jeremy R Hammond1* , Jeet Varia PhD2 , Brian Hooker PhD2*

Affiliation:

1 Independent researcher, USA
2 Children Health Defense, 852 Franklin Ave., Suite 511, Franklin Lakes, NJ 0741, USA
*Corresponding author:

1. Jeremy R Hammond, Independent researcher, USA.

2. Brian Hooker, Children Health Defense, 852 Franklin Ave., Suite 511, Franklin Lakes, NJ 0741, USA.

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al.
2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of Biotechnology and Biomedicine. 8 (2025): 118-140.

Received: March 17, 2025
Accepted: March 25, 2025
Published: May 07, 2025

Abstract

The controversy surrounding measles, mumps, and rubella (MMR) vaccination and autism has been ongoing for over 30 years. It is rooted in the parent-led grassroots movements of the 1990s; and a case-series

clinical study in 1998 by Wakefield et al. This controversy cascaded

through numerous observational studies and US Institute of Medicine

reports, culminating in 2019 with a population-based observational study

by Hviid et al. This study was hailed at the time by the US media and

medical establishment as conclusive proof that the MMR vaccine does

not increase the risk of autism, even among “genetically susceptible

children”. However, as detailed in this critical review, Hviid et al. did not

faithfully intend or interpret the data to test this hypothesis and, therefore,

cannot possibly have falsified it. We elucidate methodological flaws,

discrepancies, irreproducibility, and conflicts of interest for Hviid et al. In

addition, the conclusion from Hviid et al. cannot be generalized to the CDC

childhood vaccination schedule. All these salient features have remained

oblivious to so many regulators, mainstream media, and professional

associations in the USA. This reveals the need for more communication

about the limitations of available evidence to facilitate informed consent

for the childhood vaccination schedule.

Keywords: MMR vaccination; Autism spectrum disorder; Observational

studies; Genetic susceptibility; Conflicts of interest

Introduction

In the 21st century, serious illnesses from measles, mumps, and rubella

(MMR) in the USA are all relatively rare [1-4], all representing mild, short-

lived and treatable infectious diseases. Complications are most common

in children with comorbidities or generally suffering from poor sanitation,

inadequate waste disposal systems and water supply, poverty, and deprivation.

Indeed, the CDC declared the elimination of endemic measles in 2000 [5]

and rubella in 2004 [6]. This was confirmed by Papania et al., with reported

incidence below 1 case per 1,000,000 for measles since 2001 and 1 case per

10,000,000 for rubella since 2004 [7]. Although mumps remain endemic in the

USA, Tappe et al. reported 4.54 cases per 100,000 persons in 2019 and 0.67

per 100,000 persons in 2023 [8]. However, in 2006, several mumps outbreaks

in the USA (≈2.2 per 100,000) [9] and Canada (≈75.6 per 100,000 for

adolescents) [10], were reported in highly vaccinated populations [11] [12].

Illness from MMR is of pale significance to the unprecedented rise of chronic

and autoimmune disorders in the pediatric population. For example, estimates

in the USA indicate 1 in 36 children are diagnosed with autism spectrum

disorder (ASD) [13], 1 in 10 with attention deficit hyperactivity disorder

(ADHD) [14], 1 in 12 with asthma [15], 1 in 4 with a food allergy [16], and

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2119

1 in 5 with one or more chronic diseases [17]. Vaccines have

been hailed as one of the greatest medical advances of the past

160 years [18]. Indeed, MMR vaccination has been declared

the protagonist for the demise of MMR in the Western world.

However, as discussed by Guyer et al. [19] “Nearly 90% of

the decline in infectious disease mortality among US children

occurred before 1940 when few antibiotics or vaccines were

available.” Hence, “vaccination does not account for the

impressive declines in mortality seen in the first half of the

century.” In addition, evidence detailing the durability and

longanimity of natural immunity vs. vaccination is resounding

[20-22]. This also has further implications for infants whose

early protection derives from passive maternal immunity via

the placenta or postnatally via breast milk [23-25]. Moreover,

natural infections experienced during childhood, such as

measles and mumps, can encourage normal immune system

development, with reports of protecting effects against

Parkinson’s disease [26], chronic lymphoid leukemia [27],

cardiovascular disease [28], follicular B-cell non-Hodgkin

lymphoma [29] and allergies [30,31]. Evidence that surviving

measles infection confers beneficial effects beyond lifelong

protection from measles disease further indicates the need for

policymakers to consider natural immunity as an opportunity

cost of vaccination. It also reinforces the necessity for long-

term studies comparing a broad range of health outcomes,

including all-cause mortality, between fully vaccinated and

completely unvaccinated children [32].

In 2013, a Cochrane collaboration research review by

Demicheli et al. [33], reported significant evidence of adverse

events from MMR vaccines. Although the scientists did not

present statistical confirmation of the existence or a reliable

relationship between MMR vaccinations and ASD diagnoses,

they did report finding that “problematic internal validity in

some included studies and the biases present in the studies

(selection, performance, attrition, detection, and reporting)

influenced our confidence in their findings”; that “The design

and reporting of safety outcomes in MMR vaccine studies,

both pre- and post-marketing, are largely inadequate”; and

that “The evidence of adverse events following immunization

with the MMR vaccine cannot be separated from its role

in preventing the target diseases.” Indeed, as discussed by

Miller [34], MMR vaccination has many documented safety

deficits that counteract well-publicized benefits. For example,

MMR vaccination has been attributed to the increased risk of

emergency hospitalizations, seizures, and thrombocytopenia,

a serious bleeding disorder.

The US government and mainstream media routinely

propagate the claim that scientific studies have conclusively

demonstrated that vaccines cannot cause ASD. The Centers

for Disease Control and Prevention (CDC) authoritatively

declares on its website that “vaccines do not cause autism”

[35]. To support its bold proclamation, the agency cites

several reports commissioned by the Institute of Medicine

(IoM), now the National Institute of Medicine: in 2004

(“Immunization Safety Review”) [36], 2011 (“Effects of

Vaccines: Evidence and Causality”) [37], and 2013 (“The

Childhood Immunization shedule and Safety”) [38]. The

2004 report concluded “that the evidence favors rejection

of a causal relationship between MMR vaccine and autism.”

(p. 7). However, the same IoM report acknowledges “the

possibility that MMR could contribute to autism in a small

number of children because the epidemiological studies

lacked sufficient precision to assess rare occurrences; it was

possible, for example, that epidemiological studies would not

detect a relationship between autism and MMR vaccination

in a subset of the population with a genetic predisposition

to autism. The biological models for an association between

MMR and autism were not established but not disproved” (p

4). Although the 2004 IoM subtitled the report “Vaccines and

Autism” and has erroneously been construed to indemnify

all vaccines from the autism epidemic, the committee only

ruled on a single vaccine and a single ingredient, the MMR

vaccine or the use of thimerosal, respectively. Concerning the

MMR vaccine, the. 2004 IoM acknowledged “the possibility

that MMR could contribute to autism in a small number of

children” (p 4) and that the types of observational studies

that had been done “would not detect a relationship between

autism and MMR vaccination in a subset of the population

with a genetic predisposition to autism” (p 4). The IoM 2011

report further concluded as the 2004 IoM report that the

evidence favors a rejection of a causal relationship; however,

this conclusion was based principally on four observational

studies, each failing to consider the possibility of “genetically

susceptible subpopulations.” The 2013 IoM report was an

update to earlier reports addressing the safety of the entire

infant/child immunization schedule. The committee found

that “Studies designed to examine the long-term effects of

the cumulative number of vaccines or other aspects of the

immunization schedule have not been conducted” (p 5).

Consequently, the IoM reviews fail to support the claim for

which the CDC cites them.

Wakefield et al. 1998

Media, institutional, and public hysteria surrounding

the MMR vaccine can be traced back to a case series

clinical study of 12 children with regressive developmental

disorder, including nine with ASD, by Wakefield et al. in

1998 [39]. In 2004, the same year that the IoM issued its

report concluding that “no convincing evidence exists for

the casual MMR autism”, the Lancet published “retraction

of interpretation” for Wakefield et al. [40], with a full

retraction in 2010. This culminated in what can essentially

be described as the “professional castration” of lead author

Andrew Wakefield and coauthor John Walker-Smith in 2010

by UK journalist Brian Deer in the British Medical Journal

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2120

[41-43]. In this case series clinical report, Wakefield et

1. describe a pattern of inflammatory disorders of the gut

(colitis and ileal-lymphoid-nodular hyperplasia) in children

with autism in association with MMR vaccination. Of note,

the hypotheses generated by the study, although perceived at

the time as almost idiosyncratic, were not new. Work here

followed previous speculation from 1994 by Wakefield and

coworkers of a causal relationship between the measles virus

[44-46] and MMR vaccination [47] with Crohn's disease. In

the conclusions of their 1998 publication, Wakefield et al.

explicitly stated, “We did not prove an association between

measles, mumps, and rubella vaccine and the syndrome

described. We have identified chronic enterocolitis in

children that may be related to neuropsychiatric dysfunction.

In most cases, the onset of symptoms was after measles,

mumps, and rubella immunization.” Although they do

suggest, “Further investigations are needed to examine

this syndrome and its possible relation to this vaccine.”

To this day, a causal association between ASD and MMR

vaccination is still heavily contested. However, nearly 26

years after its publication, as speculated by Wakefield and

coworkers in the early '00s [48,49], substantial evidence

provides not only a correlational but causal relationship

between gut inflammation, gut pathology, and the gut-brain

axis in the etiology, pathogenesis, and pathophysiology of

ASD [50]. Indeed, in 2010, an expert panel of the American

Association of Pediatrics (AAP) “an organization of

60,000 pediatricians” [51], strongly recommended further

investigation into the role of gastrointestinal abnormalities in

children with ASD [52].

The controversy over MMR and ASD can and should

be further traced to a social movement of parents who

mobilized around concern over the MMR vaccination,

dating from the early 1990s in the UK. Parents reported

developmentally normal infancy with sudden regression

around the middle of their second or fourth year [53].

Children become withdrawn, with symptoms later diagnosed

as part of the autistic spectrum, along with severe and

painful bowel problems. Reflecting on the timing, many

parents came to link developmental regression and autistic

symptoms to MMR vaccination is defined here as “abuse

aimed at making victims question their sanity as well as the

veracity and legitimacy of their perspectives and feelings”

[54]. The plight of the patients was further compounded

by their experiences of limited governmental and societal

recognition of their accounts. Medical gaslighting is not new

to MMR and ASD, with growing recognition that the modern

allopathic “diagnose-protocol-prescription-paradigm” has

created a wider gap between the practitioner and patient

[55]. Indeed, medical gaslighting appears to be becoming

more common, especially for those illnesses reported to

be vaccine-induced [56] or contested [57]. The gaslighting

and shared experiences and understanding of parents who

reported injury and developmental delays in association with

MMR vaccination ultimately led to a “parental-Wakefield

alliance.” Their media reportage became a serious concern

to scientists and policymakers embroiled in public health

and vaccination in the UK, Europe, and the USA. Leach

frames this as a contrasting individual or paternal vs. public

commitment [58]. Parents were primarily concerned about

what they saw as the vaccine-damaged health of their

children. Government policymakers and their supportive

scientific networks had institutional commitments to the

continued integrity of a vaccination program with its public

obligations and population-level imperatives. Some mention

must also be given to the interests of the pharmaceutical

industry [59], i.e., “blockbuster” monopoly and profit margin

for their shareholders, maximized through millions spent on

marketing and lobbying for their products [60].

Scientific speculations, controversy, criminal allegations,

and nuances [61,62] concerning the case of Wakefield et

al., are certainly not the spotlight of this study. However,

the vitriol, hysteria, and polarization of perspectives

highlighted above give the backdrop, along with a cascade

of observational studies investigating the association between

MMR vaccination and ASD [63,64]. The debate turns, in part,

on the significance attributed to epidemiological as opposed

to clinical evidence and on the status attributed to parents’

observations and paternal instincts [65], culminating in 2019

with the publication of Hviid et al.

Hviid et al. 2019

In 2019, an observational study by Hviid et al. [66]

was published that was hailed by the mainstream media,

especially in the USA, as demonstrating irrevocably that the

MMR vaccine cannot cause autism, even among “genetically

susceptible children.” The study was published in the journal

Annals of Internal Medicine on March 5, 2019, and titled

“Measles, Mumps, Rubella Vaccination and Autism: A

Nationwide Cohort Study.” It was authored by Anders Hviid,

Jørgen Vinsløv Hansen, Morten Frisch, and Mads Melbye.

The AAP claimed, “Another study has confirmed children

who receive measles, mumps and rubella vaccine (MMR) are

not at increased risk of autism”, and that the findings “also

held for vaccinated children with a sibling who had been

diagnosed with autism. Among girls, the risk of autism was

lower in those who were vaccinated” [67]. Here are some

further illustrative examples of how the US mainstream

media reported on the study by Hviid et al.:

• A CNN headline declared, “MMR vaccine does not cause

autism, another study confirms.” Emphasizing that the

“biggest contribution of the study was the inclusion of

children at risk of autism”, CNN reported that vaccines

do “not increase the risk of autism and does not trigger

autism in children who are at risk” [68].

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2121

• A headline from National Public Radio (NPR) similarly

declared, “A Large Study Provides More Evidence That

MMR Vaccines Don’t Cause Autism.” This article quoted

lead author Anders Hviid conclusively stating that “MMR

does not cause autism.” The study, according to NPR,

“found no increased risk among subgroups of children

who might be unusually susceptible to autism, such as

those with a brother or sister with the disorder” [69].

• The headline of a LiveScience article about the study

stated, “Confirmed: No Link Between Autism and Measles

Vaccine, even for ‘At Risk’ Kids” [70].

• A headline in the New York Times trumpeted, “One More

Time, With Big Data: Measles Vaccine Doesn’t Cause

Autism” [71].

• “Another Massive Study Finds Measles Vaccine Doesn’t

Cause Autism”, said the headline of a Healthline article

that quoted coauthor Mads Melbye saying, “It’s time to

bury the hypothesis that MMR causes autism” [72].

• MedicalNewsToday reported, “MMR vaccine does not

cause autism, even in those most at risk” [73].

• “Study Again Confirms No Link Between MMR Vaccine

and Autism”, read the headline of a Psychiatry Advisor

article claiming that the study showed the vaccine “does

not trigger autism in children who are susceptible to the

disorder” [74].

• The New Yorker magazine stated, “The science on this

point is settled, to the extent that any science ever is, in

the pursuit of proving a negative” [75].

The media characterized the study as rejecting the

hypothesis of a causal association between MMR vaccine

and autism in “susceptible children.” However, as discussed

shortly, Hviid et al. excluded children who had any one

of several genetic conditions specifically because those

conditions are associated with an increased risk of autism.

Not one of those media reports relayed this salient fact to

readers. Nor, for that matter, was there even the slightest

critical examination by the media or the AAP of the study’s

methodology, findings, and conclusions. Contrary to what

we’ve been told by mainstream media, as discussed in

this critical commentary, the study of Hviid et al. cannot

conclusively demonstrate that the MMR vaccine does not

cause ASD in “susceptible children.” Moreover, it certainly

also does not falsify the hypothesis that the MMR vaccine

or vaccines administered according to the CDC’s schedule

can contribute to the development of ASD in susceptible

children. Indeed, there are substantial nuances within the

study by Hviid et al., a critical examination of which reveals

that it was not faithfully applied to test this hypothesis and

therefore cannot possibly have falsified it.

Study Overview

Aims

A preceding retrospective cohort study (children born

in Denmark 1991 – 1998) by Madsen and colleagues,

including Hviid and Melbye, was published in 2002 in The

New England Journal of Medicine (NEJM) [76], and titled,

“A population-based study of measles, mumps, and rubella

vaccination and autism.” Using analogous methodologies

and data sources, Madsen et al. 2002 concluded as Hviid

et al. that “This study provides strong evidence against the

hypothesis that MMR vaccination causes autism.” Hviid et

1. referred to this previous study and stated, “In this study,

we aimed to evaluate the association again in a more recent

and nonoverlapping cohort of Danish children that has

greater statistical power owing to more children, more cases,

and longer follow-up”, and “To evaluate whether the MMR

vaccine increases the risk for autism in children, subgroups of

children, or periods after vaccination.” The authors note the

criticism that the earlier study “did not address the concern

that MMR vaccination could trigger autism in specific groups

of presumably susceptible children.” They claimed that their

new study “addresses this concern in detail” by evaluating

“the risk for autism after MMR vaccination in subgroups of

children defined according to environmental and familial

autism risk factors.”

Study Design, Methodology and Demographic, and

Conclusions

The authors analyzed data for 663,236 children born in

Denmark to Danish-born mothers from January 1, 1999,

through December 31, 2010. Of these children, 5,775 were

excluded, resulting in a cohort of 657,461 children. The

observation period was from age one until August 31, 2013,

so the earliest-born children had reached the age of fourteen

by the end of follow-up, whereas the latest-born were still

as young as two years. The total number of children who

were followed until the end of the study was 650,943, and

among these children, 6,517 (1%) had received a diagnosis

of autism as of the follow-up end date. The average age of

autism diagnosis for their study population was 7.22 years for

children born in Denmark from January 1994 – 1999. Parner

et al. by contrast, reported in 2008 that the average age of

autism diagnosis in Denmark was 5 – 6 years, observing a

decrease in the age of diagnosis over the study period [77].

Overall, the Hviid et al. study population was about 95%

“vaccinated”, with an average vaccination age of 1.34 years

(≈ 16 months). Among children with autism, 5,992 (92%),

were “vaccinated” and 525 (8%) were “unvaccinated.”

Hviid et al. summarize their methodology as follows;

“Survival analysis of the time to autism diagnosis with Cox

proportional hazards regression was used to estimate hazard

ratios of autism according to MMR vaccination status, with

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2122

adjustment for age, birth year, sex, other childhood vaccines,

sibling history of autism, and autism risk factors (based on a

disease risk score).”

The Cox regression model has been primarily applied

by researchers for time-to-event analysis and allows one

to estimate the hazard ratio (HR) of a given endpoint

associated with a specific risk factor. Analysis by survival

or time-to-event is frequently used in epidemiological and

clinical studies [78]. As discussed by Anderson et al., time-

to-event data typically feature challenges related to, among

other things, censored observations and changes over time

in the absolute or relative risks, as well as in the values of

the predictors. In the context of “rare events” like autism,

such approaches can suffer from erratic behavior [79]. A

fundamental assumption underlying the application of the

Cox model is proportional hazards; in other words, the effects

of different variables on survival are constant over time and

additive over a particular scale [80]. The chosen methodology

also involved comparing the cumulative incidence of autism

for the “vaccinated” and “unvaccinated” cohorts, calculated

as the number of new events or cases of a disease divided by

the total number of individuals in the population at risk for

a specific time interval. Thereby, a child remained “at risk”

of developing autism until they received an autism diagnosis

or were otherwise “censored” from the study, meaning that

they ceased to be included in the population of children under

observation and hence ceased contributing to “person-years”

at risk.

Children in the cohort contributed person-time to follow-

up from 1 year of age to the end of the study on 31 August

2013, until a first diagnosis of autism, or censorship. So, for

example, a child born in 1999 who was uncensored from

the study until its end without having received an autism

diagnosis would have contributed 14 years of “person-time”

(or “person-years”) at risk, whereas a child born the same

year who received an autism diagnosis in 2004 would have

contributed five person-years at risk. The incidence rate

among the study population was 129.7 cases of diagnosed

autism per 100,000 person-years. Children were excluded due

to diagnosis of any of several genetic disorders or conditions

or censored due to death, emigration, or disappearance.

The key finding from the main analysis of the study was

that “vaccinated” children were not at a higher risk of autism

than “unvaccinated” children. As stated in the abstract,

“Comparing MMR-vaccinated with MMR-unvaccinated

children yielded a fully adjusted autism hazard ratio of 0.93

(95% CI, 0.85 to 1.02).” Figure 3 from Hviid et al. further

summarizes HRs, confidence intervals, and p-values of

correlation. Except for the reduced association of autism

and the MMR vaccination for females (HR = 0.79, 95%

CI = 0.64 – 0.97) all p-values were > 0.05, indicating no

significant association. On this basis, the authors made bold

conclusions that “The study strongly supports that MMR

vaccination does not increase the risk for autism, does not

trigger autism in susceptible children, and is not associated

with clustering of autism cases after vaccination. It adds to

previous studies through significant additional statistical

power and by addressing hypotheses of susceptible subgroups

and clustering of cases.” However, there are numerous

reasons why their findings can and should not support these

bold conclusions, including major study flaws, numerous

discrepancies, and unexplained analysis; salient features of

which remained oblivious to regulators, associations, and

mainstream media in the USA.

Study Design Flaws

Misleading definition of “genetic susceptibility”,

exclusion of children with high susceptibility and

inadequate sample size

One of the criticisms of the studies cited by the CDC

to support its claim that “vaccines do not cause autism” is

that they do not consider the possibility of “susceptible

subpopulations.” Hviid et al. acknowledge this and state,

“Specific definitions of susceptible subgroups have been

lacking.” The authors reference and follow the lead of Jain et

1. [81] in defining “genetic susceptibility” merely as having

“a sibling history of autism” at the time of study entrance.

Therefore, if a child had an autistic sibling, but the sibling

was not diagnosed until after the child had entered the

study, then the child would have been misclassified as not

“genetically susceptible.” Likewise, if a child had a genetic

or environmental susceptibility but had no siblings, the

child would have been wrongly classified. 49% of the study

population was defined as having no “genetic susceptibility”

simply by being an only child, as there were 319,936 children

with no siblings out of a study population of 657,461.

The central dogma that autism is a highly heritable

genetic disease is under debate. In 2011, Hallmayer et al.

[82], in the largest twin study to date, reported moderate

genetic heritability of 37-38% [83]. Later in 2014, using an

epidemiological sample from Sweden, Gaugler et al. [84]

concluded that autism’s genetic architecture has a narrow-

sense heritability of ≈52.4%, with most due to the common

variation and rare de novo mutations. Considering current

evidence of moderate autism genetic heritability, if a child

had a genetic susceptibility and one or more siblings, but no

siblings sharing the genetic trait or environmental trigger,

the child would be wrongly classified as not “genetically

susceptible.”

Moreover, and counterintuitive to the stated aims of the

study, while touting their study as being designed to “address

the concern that MMR vaccination could trigger autism in

specific groups of presumably susceptible children”, Hviid et

1. excluded 620 children who received a diagnosis during

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2123

the first year of life of any of the following genetic disorders:

neurofibromatosis, tuberous sclerosis, Angelman syndrome,

Fragile X syndrome, Prader-Willi syndrome, Down syndrome,

and DiGeorge syndrome. All these disorders demonstrate a

higher rate of comorbidity with autism [85-91]. While they

did not explain their rationale for these exclusionary criteria,

their working assumption was presumably as follows: if these

children were later diagnosed with autism, then it was due to

their underlying condition and not vaccination. However, that

syllogism is a non sequitur fallacy; the conclusion doesn’t

follow from the premise. In effect, Hviid et al. treated all these

conditions as competing hypotheses. One would contend

they should have treated them as potential risk factors or

indicators of epigenetic susceptibilities that might predispose

these children to vaccine injury manifesting as symptoms of

autism. Therefore, by excluding those children, the authors

acted directly contrary to their stated purpose to investigate

if “vaccination could trigger autism in specific groups of

presumably susceptible children.”

As we have seen, the media touted this study as “large”,

quoting a study population of 657,461. However, what the

media consistently failed to point out is that only a small

number met the authors’ definition of being “genetically

susceptible”, with only 838 (0.13%) children meeting the

criterion of having a sibling with autism. Following on, the

reported HR for “siblings with autism” indicated an HR of

2.69 for autism (95% CI 0.58 – 12.63) among those who

received the MMR vaccine compared to those who didn’t.

Although this correlation was not statistically significant,

one can speculate the result may have been significant if

the authors had not excluded the 620 children with genetic

disorders. We will never know since the authors have refused

to release their underlying data to other scientists to be able to

reproduce the authors’ findings.

Apart from genetic factors, Hviid et al. developed an

“autism risk score” based on several “environmental autism

risk factors”, but these were limited to “maternal age,

paternal age, smoking during pregnancy, method of delivery,

preterm birth, 5-minute Apgar score, low birth weight,

and head circumference.” Although a low 5-minute Apgar

score, low birth weight, and large head circumference may

be indicative of a developing autism phenotype, it would

be incorrect to label them as “risk factors” in the etiology

or pathogenesis of ASD. In addition, apart from “smoking

during pregnancy”, there is no consideration for assessment

of the risk from xenobiotic environmental insults. This

includes a long legacy of scientific literature spanning many

decades implicating exposure to pharmaceuticals, industrial

chemicals, and toxic and heavy metals in the etiology of

ASD [92]. Future studies should apply a more rigorous risk

assessment of exposure to environmental toxins [93-95] and

other socioeconomic factors. For example, scientists could

develop a risk score for exposure to environmental toxins

based on factors including but not restricted to geographical

location. Recent work by Palmer et al. [96] provides state-of-

the-art approaches for rigorous assessment of chemical risk

factors and intolerance in children and parents of developing

autism and ADHD. This includes a complete evaluation of

symptoms, intolerances, and life impacts of chemical, food,

and drug exposures.

The second entry for the definition of the verb “lie”

in Merriam-Webster’s dictionary is “to create a false or

misleading impression” [97]. We would infer this is precisely

what Hviid et al did when they delivered the public message

that their study proved that the MMR vaccine “doesn’t cause

autism even in children who are at greater risk of autism”

or “genetically susceptible.” Indeed, Hviid et al. defined

“genetic susceptibility” and did include children who met

their definition. However, as outlined above, such an “ad

hoc” definition of “genetic susceptibility” lacks scientific

rigor and is inadequate and misleading.

Failure to control for “healthy user bias”

Jain et al.

A “healthy user bias” has been highlighted in previous

studies for vaccination uptake [98-100]. In this scenario,

parents of children who show symptoms at an early age or

who have an older MMR-vaccinated sibling with autism,

developmental delays, or other chronic disease, are more

likely to skip the MMR vaccine, thereby biasing correlations

in favor of finding no association. This “healthy user bias”

was acknowledged by Hviid et al., who reference the study of

Jain et al., [101] which “identified lower MMR uptake rates

in children with affected siblings.” Published in 2015, Jain et

1. investigated autism occurrence by MMR vaccine status

among US children with older siblings with and without

autism. The conclusion drawn by Jain et al. was that “In this

large sample of privately insured children with older siblings,

receipt of the MMR vaccine was not associated with increased

risk of ASD, regardless of whether older siblings had ASD.”

Based on the lower vaccine uptake among children who were

considered at higher risk of autism due to “genetic factors”,

such conclusions would need reevaluation.

To illustrate, as detailed by Jain et al., whereas the MMR

vaccination rate for children with unaffected siblings was 84%

at age 2 years and 92% at age 5, by contrast, the vaccination

rate for children with autistic older siblings was 73% at age

2 and 86% at age 5. This would indicate that parents whose

first child is diagnosed with autism after receipt of the MMR

vaccine are less likely to get the shot for their second child

for fear that it might contribute to the development of autism

in the younger sibling. Similarly, parents who notice early

developmental delays might skip the MMR vaccine for

fear of it contributing to the development of autism. In the

authors’ own words, considering that lower relative risk

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2124

(RR) estimates were observed among children with autistic

older siblings versus children with unaffected siblings, “It is

possible, for example, that this pattern is driven by selective

parental decision-making around MMR immunization, i.e.,

parents who notice social or communication delays in their

children decide to forestall vaccination. Because as a group

children with recognized delays are likely to be at higher

risk of ASD, such selectivity could result in a tendency for

some higher-risk children to be unexposed . . . . It is also

plausible that parents of affected older siblings would be

especially attentive to developmental delays in their younger

children and decide to forestall immunization.” Thus, Jain

et al. reasonably hypothesized that families with one child

already affected by autism might be particularly concerned

about this for any younger siblings, resulting in a lower

vaccination rate among “genetically susceptible children.”

In addition, although not statistically significant, Jain et

1. found a negative correlation between the rate of autism

in children with an autistic older sibling and receipt of the

MMR vaccine. Rather than indicating some protective effect

of the vaccine, we would speculate this would further indicate

confounding by “healthy user bias.” This is an inherent risk

of confounding in all observational studies, which needs to be

accounted for and controlled for.

Hviid et al.

We know that Hviid et al. were aware of “health user

selection bias” because they cited Jain et al. and acknowledged

their finding of lower vaccine uptake among “susceptible

children.” Yet they failed to account for it. Indeed, Hviid

et al. affirmed that children who had siblings with autism

had 7.32 times greater HR (95% CI 5.29 - 10.12) of autism

relative to children who had siblings without autism. They

also acknowledged the finding of Jain et al. that children with

an autistic older sibling were less likely to receive the MMR

vaccine. However, based on their analysis of the Danish study

population, they claimed to have observed a vaccination

rate of 95.19% and “no appreciable differences in vaccine

uptake according to . . . . autism history in siblings.” On

closer examination of the data, alternative interpretations

are needed. For girls, the authors leaped baselessly to the

conclusion that the vaccine is protective, asserting that MMR

vaccination “reduced the risk for autism in girls.” We would

conjecture that the overall negative (HR = 0.79, 95% CI 0.64

– 0.97) association could instead be due to girls at “higher

risk” being less likely to receive the vaccine. The study’s table

of population characteristics shows that 838 of the children

in the study population had a sibling with autism, among

whom 759 (90.6%) were MMR-vaccinated and 79 (9.4%)

were not. Thus, whereas in the general study population

only 4.8% were “unvaccinated”, the proportion who were

unvaccinated among “genetically susceptible” children was

nearly double that. Figure 3 from Hviid et al. further shows

that among these 838 “genetically susceptible children”, 37

(4.4%, or 1 in 23) were diagnosed with autism. As discussed

earlier, the HR shown for this cohort indicates a 2.69 times

greater risk of autism among “vaccinated” children compared

to “unvaccinated”. Among the 37 children diagnosed with

autism, 32 were “vaccinated”, and 5 were “unvaccinated.”

Therefore, 4.2% of the susceptible vaccinated children had

an autism diagnosis compared to 6.3% of the susceptible

unvaccinated children, indicating a possible pooling of

children at “higher risk” into the “unvaccinated” group.

To approach the question from yet another angle, 759

of the 625,842 “vaccinated” children had an autistic sibling

compared to 79 of the 31,619 “unvaccinated” children.

Therefore, 0.12% of “vaccinated” compared to 0.25% of

“unvaccinated” children were “genetically susceptible.” The

“unvaccinated” were thus twice as likely to be “genetically

susceptible” according to the author’s definition. In addition,

the table shows that 319,936 children in the study had no

siblings, among whom 4.2% were “unvaccinated”, and

331,994 had siblings without autism, among whom 5.3%

were “unvaccinated.” These proportions contrast with the

9.4% of children with autistic siblings being “unvaccinated.”

Children considered “genetically susceptible” were thus 1.8

times more likely than children with non-autistic siblings and

2.3 times more likely than single children to remain MMR-

unvaccinated. Looking again at environmental risk factors

for autism, Table 1 of the study shows that 3.97% of “very-

low risk”, 4.35% of “low risk”, 5.44% of “moderate risk”,

and 6.79% of “high-risk” children remained “unvaccinated.”

Therefore, “high-risk” children were 1.25 times more

likely than “moderate risk”, 1.56 times more likely than

“low-risk” and 1.71 times more likely than “very low-risk”

children to remain MMR-unvaccinated. This would again

indicate potential confounding of “healthy user bias” with

environmental and genetic risk factors.

Hviid et al. describe their study as “by far the largest

single study to date” and state that it “allows us to conclude

from one study that even minute increases in autism risk after

MMR vaccination are unlikely, assuming unbiased results.”

If their findings instead reflect the same “healthy user bias”

identified by Jain et al., then the study by Hviid et al. does not

allow us to draw such a conclusion. Strikingly, Hviid et al.

acknowledge this limitation: “If the onset of symptoms results

in avoidance of vaccination”, they admitted, bias in favor of

no association “is possible.” Should they have said, “likely?”

Failure to consider all vaccines routinely

recommended for children in Denmark

The study of Hviid et al. focused only on the effect of the

MMR vaccine on autism rates and not the complete Danish

childhood vaccine schedule. In a secondary analysis, they

also considered other routinely administered vaccines as

covariables. From this secondary analysis, they concluded

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2125

that “MMR vaccination did not increase the risk for autism in

children characterized by other early childhood vaccinations.

. . .” However, this analysis was limited to include only “other

childhood vaccinations administered in the first year of life”,

with no consideration of vaccinations given to children after

twelve months other than the first MMR dose typically given

at fifteen months. Other vaccines considered by Hviid et al.

included five of the six vaccines recommended by Danish

health authorities for routine use in infants under one year

of age [102,103]. Hviid et al. described the “mainstays” of

the early Danish vaccine schedule as consisting of “MMR

and diphtheria, tetanus, acellular pertussis, inactivated

polio, and Haemophilus influenzae type b (DTaP-IPV/

Hib) combination.” In Denmark, the combination of DTaP,

IPV, and Hib vaccines has been recommended for infants,

each with a three-dose course. However, Hviid et al. failed

to consider that Danish authorities had since October 2007

additionally recommended three doses of the pneumococcal

conjugate vaccine (PCV) during the first year of life [104].

The introduced formulation was the 7-valent PCV7, replaced

with the 13-valent PCV13 starting in April 2010 [105]. An

additional fourth “booster” dose of DTaP-IPV combination

vaccine is also recommended at age 5 [106]. A four-dose

course of hepatitis B (HepB) vaccine was recommended in

2005 for children born to mothers who are a carrier at birth

and then 1, 2, and 3 months of age [107], which Hviid et al.

further failed to consider. The authors also failed to consider

the human papillomavirus vaccine (HPV) [108,109].

According to the World Health Organization (WHO)

[110], “The primary target group in most of the countries

recommending HPV vaccination is young adolescent girls,

aged 9-14.” In Denmark, Merck’s [111] quadrivalent HPV

vaccine Gardasil was introduced in October 2008 as a

catch-up program targeting 12-year-old girls, with routine

vaccination for girls aged 12 years starting in January 2009.

The study’s follow-up period was from January 1, 2000,

through August 31, 2013, and girls of this initial birth cohort

would have reached the age of thirteen or fourteen. While

girls born in subsequent cohorts would have been too young

to receive the HPV vaccine (unless administered earlier than

the age of 12), girls in this 1999 – 2001 cohort may have

received the HPV vaccine starting in 2011.

Thus, while this is not a flaw in the study per se, the choice

by Hviid et al. to narrow their focus fails to meaningfully

address parents’ concerns about the long-term effects on

health outcomes of the complete and extended Danish

vaccine schedule [112]. However, even if they had done such

a study, its findings would not have been generalizable to

the US childhood population since Denmark has a different

schedule than that recommended in the USA.

Failure to account for MMR formulation change

According to Hviid et al., the MMR vaccine used

in Denmark from 2000 through 2007 contained the

Schwarz strain of measles virus, which would have been

GlaxoSmithKline’s (GSK’s) “Priorix” vaccine, and a

different formulation was used from 2008 through 2013 that

contained the Enders’ Edmonton strain, which would have

been Merck’s “MMR-II.” This would indicate that children

using the Merck formulation were much too young to receive

an autism diagnosis as the oldest they would be at the time

of study is 6 years of age or younger. On further evaluation,

however, the information provided by Hviid et al. is incorrect;

they mistakenly reversed the order in which MMR vaccines

were used during those periods. According to a 2018 study on

the use of the MMR vaccine in Denmark by Sørup et al., [113]

until 2008, the Danish vaccination program used Merck’s

MMR-II, which was marketed in Europe as “Virivac” and

contained the Enders Edmonston B strain of measles virus

[114-116]. From mid-October 2008, “Virivac” was replaced

by GSK’s “Priorix”, which contained the Schwarz strain of

measles virus [117]. Since mid-June 2013, a new version

of Merck’s MMR-II has been used, which is manufactured

by Sanofi Pasteur and marketed as “MMRvaxPro”, and

which likewise contains the Edmonston strain of measles

virus [118-121]. Coauthor Christine Stabell Benn (personal

communication, August 19, 2024) [122] corresponded with

lead author Signe Sørup to confirm that the information in

their paper was correct. GSK’s Priorix was used from 2008

until 2013, not Merck’s MMR-II, as mistakenly reported by

Hviid et al. [123] (supplementary material, Appendix 1).

Following on, the average age of autism diagnosis for their

study population was 7.22 years, and the typical age of first

MMR vaccination in Denmark is 15 months. Since the study’s

follow-up period ended on August 31, 2013, children who

received “Priorix” would have been under 5 years of age and

thus, on average, too young to receive an autism diagnosis

[124]. Again, this could bias the study in favor of finding no

association between the vaccine administered to the 2008 –

2010 birth cohort and the risk of autism.

Children too young for autism diagnosis

Hviid et al., report the average age of the sample as 8.64

years with a standard deviation (SD) of 3.48 years. The

average age of autism diagnosis is reported as 7.22 years, with

an SD of 2.86 years. If the age of diagnosis follows a normal

distribution, 34.2% of the sample (z = -0.408) would be too

young to get an autism diagnosis. This could account for as

many as 3,387 additional cases not included in the analysis,

which would further bias the outcomes to favor acceptance of

the null hypothesis and no association between MMR vaccine

and autism.

Failure to consider a change of recommended age

for 2nd MMR dose

Hviid et al. did not consider the second dose of the MMR

vaccine in their primary analysis. In a secondary analysis,

they reported “no evidence of a dose-response.” However,

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2126

they failed to account for a change in the recommended age

at which the second dose was administered. The first dose of

MMR vaccine is recommended for children in Denmark at

15 months, followed by a second dose at the age of 4 years.

However, before April 2008, the second dose was routinely

administered at age 12 [125]. Therefore, children in the birth

cohorts of 1999 – 2001 and 2002 – 2004 would not have

received the second dose until years after the average age (7.22

years) of an autism diagnosis for the overall study population.

Receiving the second dose of the MMR vaccine earlier in

childhood development rather than in early adolescence may

be associated with an increased risk of autism. The inclusion

in the secondary analysis of those cohorts of older children

who did not get both doses during early childhood would

again bias the results erroneously in favor of acceptance of

the null hypothesis.

Failure to consider maternal vaccination

Maternal vaccination is another factor that Hviid et al.

failed to account for in their study. It is recognized within

the scientific community that maternal inflammation is

associated with the development of autism in the offspring

[126]. Vaccines intended to produce an immune response

involving inflammation mechanisms could infiltrate the

placenta, compromise fetal development, and increase

the risk of ASD in offspring [127-129]. In alignment with

recommendations by the WHO [130], the Danish Health

Authority, since 2010, has recommended seasonal trivalent

inactivated split influenza virus vaccination for pregnant

women with selected high-risk chronic diseases in any

trimester; and vaccination is additionally recommended for

all pregnant women in the second and third trimesters [131].

Mølgaard-Nielsen et al. report up to 10% vaccine uptake by

Danish women between 2010 – 2016. This means children

born in the last cohort and reaching the age of 3 years by the

end of the follow-up period may have been born to mothers

vaccinated during pregnancy. Future studies should account

for prenatal risk factors, including vaccination and the use of

other pharmaceuticals during pregnancy.

Exclusion of immigrants

Hviid et al. included only children “born to Danish-born

mothers from 1 January 1999 through 31 December 2010”

and registered in the Danish Medical Birth Registry, with the

exclusion of 1,498 children. Asylum seekers to Europe may

come from war-torn countries where health systems have

broken down. There is evidence that asylum-seeking children

have low coverage of childhood vaccinations in their home

countries, as well as high uptake of immunizations in host

countries [132] [133]. Therefore, immigrant children might

receive multiple vaccines, doses, and boosters at once or

spaced closer together to “catch up” on ones they may have

missed in their home country. This might place immigrant

children at higher risk of vaccine injury and developmental

disorders such as autism. In addition, children of non-Danish

ethnicity may have a higher risk of autism due to one or

more epigenetic traits. Their exclusion could further bias the

study’s findings.

Potential misclassification of study subjects

As the authors acknowledge, “A limitation of our study

is that we used the date of first diagnosis of autism, which

is probably delayed compared with the age at onset of

symptoms.” They then suggest this might bias their findings

in favor of an association between MMR vaccination and

autism by citing a hypothetical example in which “symptoms

precede vaccination and diagnosis occurs after vaccination”,

resulting in “misclassification of autism cases as vaccinated.”

While they focus on the hypothetical scenario of bias favoring

an association, they do not account for the misclassification of

“vaccinated” children as “unvaccinated.” A study published in

2017 by Holt et al. [134], using data from the Danish National

Health Service Register, addressed known concerns about the

reliability of vaccination coverage data. To that end, the study

authors compared MMR vaccination coverage according to

medical records from general practitioners with that reported

by the national registration database. Researchers report that

the national database showed significantly lower vaccine

coverage than medical records. Among the practices included

in the study, the national database showed vaccine coverage

of 86%, whereas the medical records showed coverage of

94%. The study authors state, “More than half of the children

who were unvaccinated according to the register-based data

(55%) had been vaccinated according to the medical records.”

Vaccinated children being misclassified as “unvaccinated” in

the study by Hviid et al. would, of course, bias their findings

in favor of the null hypothesis and no association.

Discrepancies in Autism Rate in the Study

Group vs. Danish Population

In Figure 1 of their study, Hviid et al. report 6,517

children with autism out of a population of 650,943,

equating to 1%. This includes only subjects followed until

the end of the study. If one takes account of the 657,461

children initially included, an autism prevalence of 0.99%

can be calculated. The prevalence of autism in Denmark

in 2016, according to a study published by Schendel and

Thorsteinsson [135], was 1.65%. Given a study population of

657,461 children, of whom 650,943 were followed until the

end of the follow-up period, at a prevalence rate of 1.65%,

we should expect there to be between 10,741 and 10,848

children with autism, whereas, in the study population, there

were only 6,517. This would indicate an under-ascertainment

of between 4,224 and 4,331. However, although the Hviid et

1. study was published in 2019, the observation period for

the study population ended on August 31, 2013. Therefore,

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2127

the prevalence of autism for that year would make the most

valid comparison. According to the study of Schendel and

Thorsteinsson among children aged 10 years, the prevalence

of autism was 1.16% by 2010 (representing the birth cohort

of 2000 – 2001), 1.33% by 2012 (birth cohort 2002 – 2003),

1.44% by 2014 (birth cohort 2004 – 2005), and 1.65%

by 2016 (birth cohort 2006 – 2007). Given an estimated

prevalence by 2012 of 1.33%, we would expect the Hviid et

1. study population to include 8,658 to 8,744 children with

autism, indicating that approximately 2,141 to 2,227 autistic

children were missing from the study. This suggests either

that Schendel and Thorsteinsson's estimated prevalence of

autism was grossly inaccurate or that the population under

study by Hviid et al. was not representative of the childhood

population of Denmark. The latter explanation is more likely

as the study of Schendel and Thorsteinsson, unlike Hviid et

al., was designed to estimate prevalence, and its findings were

consistent with CDC data for the US childhood population,

with an observed increase in the prevalence of autism for

each birth cohort [136]. By contrast, when broken down by

the age of each birth cohort, the data presented by Hviid et

1. show a decreasing prevalence of autism. Figure 3 from

Hviid et al. summarizes the total number of children with

autism for each birth cohort. This enables one to calculate the

prevalence of diagnosis based on age for each birth cohort;

namely, 1.71% for the 1999 – 2001 cohort, 1.28% for 2002

– 2004, 0.74% for 2005 – 2007, and 0.20% for 2008 – 2010.

These discrepancies would indicate methodological flaws in

the study of Hviid et al. that render their study population

non-representative. The authors do not acknowledge these

discrepancies, much less provide any explanation.

Irreproducible Findings

Reproducibility is an essential aspect of the scientific

method [137]. It is crucial to advancing scientific knowledge

because it ensures that research findings are reliable and

not due to error, chance, or bias. Without reproducibility,

scientific claims remain unverified and are therefore of

questionable reliability. While the data Hviid et al. present

show a decreasing rate of autism from one birth cohort to

the next, they contradictorily state in their paper that being in

the later-born 2008 – 2010 cohort conferred the “highest risk

for autism.” However, on inspection of Table 3 in the SI of

Hviid et. al, using the 1999 – 2001 cohort for reference, they

report an HR of 1.18 for 2002 – 2004, 1.31 for 2005 – 2007,

and 1.34 for 2008 – 2010. So, children born in 2009 - 2010

were 1.34 times more likely to be diagnosed with autism than

those born in 1999 – 2001, and so on. While this increasing

risk is what we would expect to find, as shown, it directly

contradicts the data shown in their paper. This puzzling

discrepancy was noticed by statistician Elizabeth Clarkson

(personal communication, April 4, 2019), who contacted the

Annals of Internal Medicine staff and the study’s lead author,

Anders Hviid, to inquire about this self-contradiction and to

request their raw data (supplementary material, Appendix 2)

[138]. In reply to Clarkson’s email inquiry, Hviid confirmed

that the trend shown by their HR could not be reproduced

from the data they presented in the main paper. However, he

said, they could not release their raw data because they were

“prohibited from sharing these data by Danish law.” Clarkson

then wrote the Annals editors to formally request the authors’

dataset, pointing out that “the results of this sophisticated

regression model used for the results reported in Table 3 of

the supplemental material is in direct contradiction to the

crude associations computed from the data published in the

paper itself.” In reply to Elizabeth Clarkson, the journal staff

instructed her to direct her request to the study’s authors. Since

there is a major self-contradiction between the data reported

and their calculated HRs, serious concerns must be raised

about their true scientific viability and irreproducibility.

Unexplained Risk of Autism Incidence for Boys

and Girls with Genetic Susceptibility

In the abstract, Hviid et al. included the caveat that

“no increased risk for autism after MMR vaccination was

consistently observed in subgroups of children defined

according to sibling history of autism.” One interpretation of

the adverb “consistently” would logically imply an increased

risk was observed in at least one such subgroup of children.

Indeed, for boys who had an autistic sibling, Figure 4 in the

SI of Hviid et al. illustrates the cumulative incidence, which

represents the male children who met the author’s criterion

for having a “genetic susceptibility” to autism. From about

age seven onward, the higher cumulative incidence of autism

was among the children who received the MMR vaccine.

This increased risk of autism among vaccinated boys was not

statistically significant, which may be an artifact of a small

subset of boys considered in this analysis.

The same figure illustrates the cumulative incidence

of autism among girls with an autistic sibling. From

approximately age 4 - 11, among girls with “genetic

susceptibility”, a greater cumulative incidence for those who

received the MMR vaccine is displayed. However, between

the ages of 11 and 12, there is a leap in the cumulative

incidence for MMR-unvaccinated girls from approximately

1% to approximately 9%, resulting in a greater incidence of

autism among the unvaccinated. Since the study’s follow-up

period ended in 2013, the maximum age of 14 on this graph

can only represent girls born in 1999. Comparably, only

children born in or before 2002 could have reached the age

of 11 before the study’s end. One can only speculate on the

cause of the sudden increase in the cumulative incidence of

autism at about age 11, which would be relevant to the 1999

– 2001 and 2002 – 2004 birth cohorts. The authors do not

discuss this sudden increase in cumulative incidence, which

is certainly a curiosity for which an explanation is warranted

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2128

but lacking.

Non-Generalizability to the US Childhood

Population

Taking account of the endorsement of Hviid et al. by

the USA´s media, regulators, and professional medical

organizations and their claims that the vaccine-autism

hypothesis had been falsified, the question arises if the

conclusions presented here can be generalized to the US

population. While Danish health authorities recommend

the HepB vaccine for infants (considered) at risk, the

CDC recommends a three-dose regimen of this aluminum-

containing vaccine for all infants starting from the first day

of birth. Similar to Denmark, during their first year of life,

children in the US typically receive three doses each of DTaP,

IPV, Hib, and pneumococcal conjugate vaccine (PCV15 or

PCV20); but starting at the age of 6 months, American children

also receive two or three doses of rotavirus vaccine (RV1

or RV5, respectively) and an inactivated influenza vaccine,

multi-dose formulations of which contain the preservative

thimerosal [139]. The rotavirus vaccine is not recommended

in Denmark, and whereas Danish authorities recommend

flu shots only for children aged 2 to 6 years and adults aged

65 or older, the CDC recommends annual flu shots, multi-

dose vials of which also contain thimerosal, a mercury-based

preservative, starting in infancy and continuing throughout

an individual’s lifetime. Whereas Danish children receive a

booster dose of DTaP and IPV at the age of 5 years, American

children receive a fourth dose of IPV at 4 years, and for DTaP,

a fourth dose at the age of 15 months, a fifth dose at the age

of 4 years, and a booster dose of the adolescent and adult

formulation Tdap at the age of 11 years. While in Denmark

the first dose of MMR is typically given at 15 months,

it is recommended earlier in the US, at 12 months, with a

second dose in both countries at 4 years of age. The varicella

or “chickenpox” vaccine is not on Denmark’s childhood

schedule but is recommended by the CDC at the age of 1 year

and a second dose at age 4. The hepatitis A vaccine is also

not on Denmark’s schedule, while the CDC recommends it

in a two-dose series spaced six months apart starting at the

age of 1 year. The meningococcal vaccine is another shot not

recommended for routine use in Denmark, whereas the CDC

recommends it at age 11, with a second dose at age 16. While

the HPV vaccine is recommended in Denmark for children

aged 12 years, the CDC recommends its two-dose regimen

starting at age 11 while okaying its administration for

children as young as 9. Additionally, the CDC recommends

that pregnant women receive the aluminum-containing Tdap

vaccine, the potentially thimerosal-containing influenza

vaccine, and the respiratory syncytial virus vaccine [140].

In summary, the CDC recommends upwards of 70 vaccine

doses for 17 diseases, with a whopping 29 doses (20 or more

injections) by a neonate’s first birthday. At a two-month

“well-childcare visit”, an infant may receive as many as six

vaccines for eight pathogens. In comparison, the Danish

schedule consists of twelve shots for six pathogens, with

only four vaccines by their first birthday (three doses each of

DTaP, IPV, Hib, and PCV13). Once again, so many opinion

leaders, regulators, media, and professional associations in

the USA were oblivious to these salient differences.

Conflicts of Interest

The stakes in the ASD debate are high. Over half a century,

there has been a dramatic increase in ASD rates [141].

Identifying causative factors for ASD is already a challenging

task for the scientific community, demanding the highest

standards of openness and transparency. Any departure from

these standards represents a disservice to all. The financial

stakes in vaccine research are also high. The global biologics

market was US$511.04 billion in 2024 and is expected to reach

around US$1,374.51 billion by 2033 [142]. The approval and

subsequent commercialization of gene therapy candidates are

expected to drive growth in the biologics market. The vaccine

market worldwide was valued at US$81.06 billion by 2023

and is anticipated to reach around US$152.45 billion by 2033

[143]. In the U.S., the COVID-19 vaccine market transitioned

to a commercial phase following the depletion of the federal

government’s purchased stock. The global mumps vaccine

market was valued at US$2 billion in 2021 and is projected to

reach US$3.5 billion in 2031 [144].

When conflicts of interest influence research, the

resulting scientific debate on safety and efficiency, etc.,

can be confounded by misleading information. Indeed, to

ensure scientific quality, manuscripts authored by CDC staff

are required to undergo an internal review and approval

process known as clearance. As part of the domain of ethical

standards, “free from conflicts of interests” is explicitly stated

[145]. Kern et al., [146] summarize past and current examples

of research conflict of interest and outside influences for

tobacco, lead, methylmercury, atrazine, bisphenol A, and

olestra. The CDC receives millions of dollars in industry

gifts and funding, including substantial support from the

pharmaceutical industry [147,148]. Miller and Goldman

[149] and Hooker [150,151] provide firsthand details of how

the CDC suppressed and disallowed deleterious vaccine

data from being published and engaged in other acts of

questionable scientific integrity. Nissen [152] discusses the

dependence of professional medical associations on industry

funding [153].

Physicians and the public rely on journals as unbiased

and independent sources of information and to provide

leadership to improve trust in medicine and the medical

literature. Yet financial conflicts of interest have repeatedly

eroded the medical profession's and journals’ credibility

[154]. During the past decade, two former editors-in-chief

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2129

of the NEJM, Marcia Angell and Arnold Relman, have

spoken out about the excessive power of the pharmaceutical

industry over medical research, hospitals, and doctors. In a

letter to the New York Times on December 28, 2004 [155],

they pointed out that in the previous year, one drug company

had spent 28 percent of its revenues (more than $6 billion)

on marketing and administrative expenses. They concluded,

“The medical profession should break its dependence on the

pharmaceutical industry and educate its own.” In an article in

the New York Review of Books on January 15, 2009, Angell

wrote, “It is simply no longer possible to believe much of the

clinical research that is published, or to rely on the judgment

of trusted physicians or authoritative medical guidelines”

[156].

Hviid et al.

Hviid and his three coauthors (Hansen, Frisch, and

Melbye), at the time of the study’s publication, were affiliated

with the Statens Serum Institut (SSI), which develops

vaccines and is “responsible for the purchase and supply

of vaccines to the Danish national vaccination programs”

[157]. Like the CDC, the SSI is a government agency and

research institute; its purpose is to “ensure preparedness

against infectious diseases and biological threats as well as

control of congenital disorders.” For vaccine research, the

SSI is “devoted to vaccines against tuberculosis, chlamydia,

HIV and novel adjuvants to direct and potentiate the immune

responses.” Upon the study’s publication, the SSI issued a

press release proclaiming that it “once again invalidates

the claim that the MMR vaccine increases children’s risk of

developing autism” [158].

Financial support was provided by the Novo Nordisk

Foundation [159,160] and the Danish Ministry of Health

[161]. The Novo Nordisk Foundation is a charitable

foundation that issues funding grants for scientific research

while owning the holding company Novo Holdings A/S

[162], the majority voting shareholder in the Danish

pharmaceutical corporation Novo Nordisk [163]. Novo

Nordisk is a large multinational pharmaceutical company

in Denmark with a market capitalization greater than

US$497 billion [164]. According to their annual report,

they anticipated an effective 2019 tax rate of 20-22%; the

government of Denmark receives significant tax revenue

from Novo Nordisk. Both the Danish Ministry of Health and

Novo Nordisk have a vested interest in a study that might

influence the demand for the MMR vaccine. Also of note,

Novo Holdings A/S investments include vaccine companies

[165]. For example, in April 2019, the group invested tens

of millions of dollars into Oxford Biomedica, which was

involved in a consortium to develop and manufacture the

AstraZeneca COVID-19 vaccine [166,167]. In December

2023, the Novo Nordisk Foundation Initiative for Vaccines

and Immunity (NIVI) was announced, [168] which is a

partnership between the University of Copenhagen, and the

SSI [169,170]. The stated goal of NIVI is “to revolutionize

and accelerate vaccine development in Denmark by bridging

the gap between academic research and industry innovation.”

Simultaneously, the foundation established a limited

liability company, the Novo Nordisk Foundation Vaccine

Accelerator, to “facilitate the translational efforts of NIVI

by providing industry-level expertise in vaccine development

and conducting the early clinical testing of our vaccine

candidates” [171]. Predating its vaccine initiative, the Novo

Nordisk Foundation had funded numerous researchers in SSI

and other institutions active in vaccine-related research [172-

177]. The foundation also funded the SSI “Danish National

Biobank”, which aims to grant scientists access to data on

residents in Denmark from national health registries along

with information about biological samples [178]. The Danish

Ministry of Health and the SSI unquestionably have a stake

in preserving their own credibility and existing policies, not

unlike the United States Department of Health and Human

Services and CDC. However, as summarized by Fig. 1 and

as is the documented case with American regulatory agencies

and professional bodies [179], an inherent conflict of interest

in researching, marketing, and supplying childhood vaccines

becomes apparent, if not explicit.

Figure 1: Ceonflicts of Interest Concerning Hviid et al.

Annals of Internal Medicine

Two editors of the Annals of Internal Medicine, Jaya K.

Rao (Deputy Editor) and Catharine B. Stack (Deputy Editor

for Statistics), disclosed holding stocks in pharmaceutical

companies active in vaccine research and manufacture. This

includes Eli Lilly, Pfizer, and Johnson and Johnson. Eli Lilly

is a former manufacturer of Dr. Jonas Salk’s inactivated polio

vaccine and the developer of the mercury-based preservative

thimerosal [180].

Discussion

In 2019, the AAP and mainstream media in the USA

hailed the study by Hviid et al. as additional proof that the

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2130

MMR vaccine does not increase the risk of ASD, even among

“genetically susceptible children.” But the fact is that the study

authors excluded children with any one of several genetic

conditions placing them at higher risk, with an inadequate

definition of “genetic susceptibility.” Based on highlighted

methodological flaws, discrepancies, and conflicts of interest,

we would venture that the outcomes from Hviid et al. would

not indicate evidence of a lack of association between ASD

and MMR but, instead, researcher bias to a priori serve

the status quo. As an antidote, we would prescribe diligent

scientists working in the field to take note and learn from

Hviid et al. with a priori consideration of selection bias

and risk factors, “healthy user bias”, and data calibration

with positive and negative controls [181], which would

provide paths to much-needed rigor in observation studies;

especially when the stakes are so high, with CDC objectives

for ubiquitous vaccination in pediatric populations.

Hviid and coworkers have used similar methodologies to

assess risks of other adverse events and disorders from MMR

vaccination and other pharmaceuticals used in pregnancy or

childhood. For example, Hviid and coworkers have reported

no association between ASD and thimerosal-containing

vaccines [182]; no evidence of causality for childhood

vaccination and type 1 diabetes [183]; an increased rate of

febrile seizure following MMR vaccination deemed “small

even in high-risk children” [184]; no significant association

between maternal use of selective serotonin reuptake inhibitors

during pregnancy and ASD in their offspring [185]; and no

association between Ondanse (prescribed for nausea and

vomiting) and increased risk of adverse fetal outcomes [186].

We would note that in studies for febrile seizure and type I

diabetes in pediatric populations, the “genetic susceptibility”

evaluation, as for Hviid et al. 2019, was based on family

history, i.e., sibling history of adverse events or diabetes

diagnosis. Clinical and preclinical evidence of adverse events

from these pharmaceuticals is well documented [187-190].

Further critical analysis of these studies, as provided here for

Hviid et al. 2019, would be prudent, commended, and much

needed.

In a famous case, the government acknowledged that the

administration of nine vaccine doses at once to a 19-month-

old girl named Hannah Poling “significantly aggravated an

underlying mitochondrial disorder, which predisposed her to

deficits in cellular energy metabolism and manifested as a

regressive encephalopathy with features of autism spectrum

disorder” [191]. At the time, then CDC director Julie

Gerberding admitted on CNN [192], “Now, we all know that

vaccines can occasionally cause fevers in kids. So, if a child

was immunized, got a fever, had other complications from

the vaccines, and if you’re predisposed to a mitochondrial

disorder, it can certainly set off some damage. Some of the

symptoms can be symptoms that have characteristics of

autism.” Notably, in 2009 Gerberding left her government

job to work for the pharmaceutical giant Merck as president

of their vaccine division and later became responsible for

“strategic communications” as Chief Patent Officer and

Executive Vice President of the Company, Population Health

& Sustainability [193,194].

Indeed, a growing body of evidence implicates a strong

interplay between environmental insults and epigenetics in the

etiology and pathogenesis of ASD [195]. Bradstreet argued in

a presentation given to the Vaccine Safety Committee in 2004

[196] that, “meaningful epidemiological studies should test

a priori hypotheses that derive from all clues evident in the

clinical histories of affected children . . . .” We would concur

and endorse future prospective observational studies that

truly account for epigenetic and environmental risk factors

as part of the wider “ecological exposome” [197]. Although

a non-trivial task, the SSI biobank initiative provides Danish

researchers access to “25 million biological samples” [198],

which should be ample and adequate to define and address

the association between genetic susceptibility, MMR, and

ASD. In a 2014 interview with journalist Sharyl Attkisson,

the CDC’s Director of the Immunization Safety Office, Frank

DeStefano, acknowledged that “it’s a possibility” that vaccines

could trigger ASD in “genetically susceptible individuals”,

but that it is “hard to predict who those children might be”,

and trying to determine what underlying conditions put

children at greater risk of being injured by vaccines is “very

difficult to do” [199]. Indeed, researchers at the CDC have

acknowledged that no observational study “can definitively

establish or disprove the hypothesis that thimerosal exposure

increases the risk of ASDs”, which would instead require “a

large-scale prospective randomized trial” [200].

No golden standard exists to judge if an observed

association (or non-association) is genuine [201]. Placebo-

controlled randomized clinical trials (RCT), although

also prone to error [202], remain the gold standard for the

inference of causality. However, no placebo-controlled RCT

has investigated individual vaccines, let alone the overall

effects of the vaccine schedule, for long-term health outcomes

between vaccinated and unvaccinated children, including

all-cause mortality. The common consensus among FDA

regulators is that it is unethical to do “vax-unvax” clinical

studies with true saline placebos [203]. We would agree,

inasmuch as puncturing any baby’s skin over the course of a

year with at least 20 intramuscular injections of saline placebo

or multiple “biologic pharmaceuticals”, all formulated

differently, many in one sitting, as part of any clinical study,

would not only be unethical but barbaric. Moreover, this is

an exemplary example of the petitio principii fallacy and

institutional cognitive dissonance for vaccine research since

it presumes a priori that the potential benefits outweigh any

possible risks, which is precisely the proposition that should

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2131

have been determined, as also argued by Bradstreet, through

properly designed, rigorous, and robust RCTs. Despite this,

a word of caution would be prudent. We would state that no

“magic bullet” exists for testing causality, especially for rare

and/or long-term serious adverse events. Indeed, questions

of causality cannot be answered by RCTs alone because of

the inherent low power in such studies [204]. Some discourse

must also be given to the manufacturing of pharmaceutical

biologics. Whereas the chemical synthesis of a small

molecule drug may have a dozen steps that must be monitored

and controlled, the fermentation process for vaccines may

have hundreds [205]. Valiant et al. [206] and Chooi et al.

[207] provide ample examples of past and current reports of

contamination issues and vaccine recalls. Unquestionably,

it is an important risk factor for vaccine injury, as would

be the case for any pharmaceutical intended for ubiquitous

prophylaxis of pediatric populations [208].

The challenges in making inferences from the evidence

are no less great (but not particularly greater) when the

evidence is based on large observational studies, as per Hviid

et al. (or a small clinical case series, as per Wakefield et al.).

However, if one truly takes an evidence-based approach, it

would be ill-advised to be complacent about immunization

and assume its innocence based on observational studies

or even systematic reviews of the evidence [209]. As

early as 2004, Price, Jefferson, and Demicheli highlight

methodological issues arising from systematic reviews of

vaccine safety, especially for rare and/or long-term serious

adverse events [210]. Moreover, a growing body of scientists,

healthcare professionals, and citizens question the benefits of

vaccines, with evidence that child mortality and disease from

infectious diseases had already decreased significantly before

the widespread use [211-213]. Based on their observations,

one can hope that immunization will become redundant

through good sanitation, adequate waste disposal systems,

clean water, nutritious food supply, wealth, and plenty for

all children [214]. Nonetheless, the possibility remains that

we may be creating long-term damage through vaccination,

demonstrated by substantially increasing levels of serious

and chronic disease, including autoimmune conditions,

especially in populations made vulnerable by acute or chronic

anthropogenic xenobiotic insult [215, 216].

Hviid et al. provide an example of how studies examining

this question concerning the MMR vaccine could be interpreted

as having been designed to find no association through design

flaws biasing findings. Moreover, to date, no studies have

been done that were designed to test the hypothesis that

vaccinating according to the CDC’s schedule can contribute

to the development of autism, chronic diseases, and all-cause

mortality in children with epidemiological susceptibility.

Therefore, scientists and medical practitioners must always

be on their guard for evidence pointing to vaccine danger, as

should be the case for side effects from any pharmaceutical

intervention [217]. Evidence alone never speaks for itself or

conveys the truth because it always requires interpretation.

Expert opinion or population-based studies are not a

surrogate for evidence-based, first-hand experience or data;

science is not about consensus, it’s about the truth [218, 219].

Moreover, acquiring the right answers also requires asking

the right questions. Barosi and Gale illustrate the point when

they state that “Accuracy refers to getting the correct answer,

and precision to getting the same answer on repetition

regardless of whether it is the correct answer or not. A wrong

answer which is reproducible is precise but inaccurate. What

we need are accurate, precise answers.” Based on the case

presented here, for Hviid et al., nothing could be more vital

for the future of vaccine research.

Closing Remarks

Vaccine safety science has become a hazardous occupation

[220]. The sanctity of vaccines has become a religious

mantra, and anyone who questions the safety or efficacy

of government-recommended vaccines or deviates from

acceptable vaccine orthodoxy is vulnerable to suppression

and personal attacks [221]. The consequences can be severe,

with harm to reputation, hindrance of research, and even

destruction of a career. The tactics of suppression reported

by the researchers and doctors in the study of Elisha et al.

[222] refer to defamatory publications on websites, retraction

of papers that pointed to safety issues with certain vaccines,

denial of research grants, calls for dismissal, summonses to

hearings or disciplinary committees by health authorities,

suspensions of medical licenses, and self-censoring.

Kempner [223] further defines the “chilling effect” regarding

the influence of political controversy on the production of

new science. It appears that so many researchers are trapped,

restrained, and handicapped in an “institutional straitjacket”

[224] to continue their studies while employing practices

specifically designed to disguise the most controversial

aspects of their research and maintain the consensus and

status quo.

Alongside this, as highlighted by this study, the public

is poorly served by the coverage of medical science in the

press. Journalists in the medical field are often accused of

being sensational, unobjective, and speculative, with a lack

of follow-up and undisclosed conflicts of interest [225,226].

To illustrate, The New York Times health writer Aaron E.

Carroll has advocated public compliance with the CDC’s

influenza vaccine recommendations, which include the

recommendation that pregnant women get a flu shot [227].

He thus treats the observational studies that the CDC relies

on to support the claim as conclusive proof that vaccination

during pregnancy is safe for both the expectant mother and the

vulnerable developing fetus. Yet when it comes to the risks

of drinking alcohol, Carroll advises his readers, “Don’t give

too much weight to observational data” [228]. Lipworth et al.

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2132

[229] venture that ‘alternative media’, while threatening the

status quo, viability, and public dependence on mainstream

media, allows patients and clinicians to engage in media-led

open debates about health-related issues based on first-hand

experience.

The autism-MMR debate is entrenched in the many

decades of grassroots movements rooted in the 1990s. All

were motivated by the medical gaslighting of mothers and

fathers, medical indifference to their paternal instinct, and

wider social ostracization of those who show any deceit toward

the accepted vaccine orthodoxy. Over 30 years later, in the

post-COVID-19 era, stereotyping, social stigma, shunning,

condescension, and polarization of parents who choose not to

vaccinate their children [230] and the vaccine injured [231]

has only been exacerbated and intensified. We would propose

a moratorium on the stigmatization and dichotomization of

the unvaccinated, the vaccine-injured, and vaccine critics and

an end to mandates for childhood vaccines for school entry.

Health freedom, parental autonomy, and open, frank scientific

debate can only foster real advancements for true service to

our children, families, and the wider society. Indeed, as stated

by Aristotle: “Science arises from curiosity.” We would

extend this to explicitly state that it certainly cannot arise

from institutional conflicts of interest, consensus, censorship,

imposition, suppression, apathy, or gaslighting.

Funding

This research received no specific grant from funding

agencies in the public, commercial, or not-for-profit sectors.

Data Availability

No data was used for the research described in the article.

Acknowledgments

Consultation, critical insights, and/or comments for the

first draft from JB Handley, James Lyons-Weiler, Stephanie

Seneff, and Elizabeth Clarkson.

Competing Interests : The author(s) declare none.

Credit Authorship Contribution Statement

Hammond created the original study conception and first

draft. Additional concept development and drafting by Varia

and Hooker. Further writing, review, and editing by Varia,

Hooker, and Hammond. All authors have read and approved

the final manuscript.

Supplementary Files Link:

https://cdn.fortunejournals.com/supply/JBB12526.pdf

References

1. Perry RT, Halsey NA. The clinical significance of

measles: A review. The Journal of Infectious Diseases

189 (2004): S4-S16.

2. Centers for Disease Control and Prevention (CDC).

Mumps. Mumps Symptoms and Complications. (2024).

3. Centers for Disease Control and Prevention (CDC).

Rubella (German Measles, Three-Day Measles). (2024).

4. DeStefano F, Shimabukuro TT. The MMR vaccine and

autism. Annual Review of Virology 6 (2019): 585-600.

5. Mathis AD. Measles—United States, January 1, 2020–

March 28, 2024. MMWR. Morbidity and Mortality

Weekly Report (2024) 73.

6. Centers for Disease Control and Prevention (CDC).

Elimination of rubella and congenital rubella syndrome-

United States, 1969-2004. MMWR. Morbidity &

Mortality Weekly Report 54 (2005): 279-282.

7. Papania MJ, Wallace GS, Rota PA, et al. Elimination of

endemic measles, rubella, and congenital rubella syndrome

from the Western hemisphere: The US experience. JAMA

Pediatrics 168 (2014): 148-155.

8. Tappe J, Leung J, Mathis AD, et al. Characteristics of

reported mumps cases in the United States: 2018–2023.

Vaccine 42 (2024): 126143.

9. Barskey AE, Glasser JW, LeBaron CW. Mumps

resurgences in the United States: A historical perspective

on unexpected elements. Vaccine 27 (2009): 6186-6195.

10. De Serres G, Markowski F, Toth E, et al. Largest measles

epidemic in North America in a decade-Quebec, Canada,

2011: Contribution of susceptibility, serendipity, and

superspreading events. The Journal of Infectious Diseases

207 (2013): 990-998.

11. Dayan GH, Rubin S, Plotkin S. Mumps outbreaks in

vaccinated populations: Are available mumps vaccines

effective enough to prevent outbreaks? Clinical Infectious

Diseases 47 (2008): 1458-1467.

12. Poland GA, Jacobson RM. Failure to reach the goal

of measles elimination: Apparent paradox of measles

infections in immunized persons. Archives of Internal

Medicine 154 (1994): 1815-1820.

13. Maenner MJ, Warren Z, Williams AR, et al. Prevalence

and characteristics of autism spectrum disorder among

children aged 8 years—Autism and Developmental

Disabilities Monitoring Network, 11 sites, United States,

2020. MMWR Surveillance Summaries 72 (2023): 1.
2021. Li Y, Yan X, Li Q, et al. Prevalence and trends in diagnosed

ADHD among us children and adolescents, 2017-2022.

JAMA Network Open 6 (2023): e2336872-e2336872.

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2133

15. Zahran HS, Bailey CM, Damon SA, et al. Vital signs:

Asthma in children—United States, 2001–2016.

Morbidity & Mortality Weekly Report 67 (2018): 149.

16. Zablotsky B, Black LI, Akinbami LJ. Diagnosed allergic

conditions in children aged 0-17 years: United States,

2021. NCHS Data Brief. No. 459. National Center for

Health Statistics. (2023).

17. Ullah F, Kaelber DC. Using large aggregated de-identified

electronic health record data to determine the prevalence

of common chronic diseases in pediatric patients who

visited primary care clinics. Academic Pediatrics 21

(2021): 1084-1093.

18. Killeen RM. Vaccines-one of the greatest medical

advances of modern times. Canadian Pharmacists Journal/

Revue des Pharmaciens du Canada, 140 (2007): S2-S2.

19. Guyer B, Freedman MA, Strobino DM, et al. Annual

summary of vital statistics: Tcrends in the health of

Americans during the 20th century. Pediatrics 106 (2000):

1307-1317.

20. Bianchi FP, Mascipinto S, Stefanizzi P, et al. Long-term

immunogenicity after measles vaccine vs. wild infection:

An Italian retrospective cohort study. Human Vaccines &

Immunotherapeutics 17 (2021): 2078-2084.

21. Horstmann DM, Schluederberg A, Emmons JE, et al.

Persistence of vaccine-induced immune responses to

rubella: comparison with natural infection. Clinical

Infectious Diseases 7 (1985): S80-S85.

22. Amanna IJ, Carlson NE, Slifka MK. Duration of humoral

immunity to common viral and vaccine antigens. New

England Journal of Medicine 357 (2007): 1903-1915.

23. Papania M, Baughman AL, Lee S, et al. Increased

susceptibility to measles in infants in the United States.

Pediatrics, 104 (1999): e59-e59.

24. Mandomando IM, Naniche D, Pasetti MF, et al. Measles-

specific neutralizing antibodies in rural Mozambique:

Seroprevalence and presence in breast milk. American

Journal of Tropical Medicine and Hygiene 79 (2008):

787-792.

25. Waaijenborg S, Hahné SJ, Mollema L, et al. Waning of

maternal antibodies against measles, mumps, rubella, and

varicella in communities with contrasting vaccination

coverage. The Journal of Infectious Diseases 208 (2013):

10-16.

26. Sasco AJ, Paffenbarger JR, RS. Measles infection and

Parkinson's disease. American Journal of Epidemiology

122 (1985): 1017-1031.

27. Parodi S, Crosignani P, Miligi L, et al. Childhood

infectious diseases and risk of leukaemia in an adult

population. International Journal of Cancer 133 (2013):

1892-1899.

28. Kubota Y, Iso H, Tamakoshi A, et al. Association of

measles and mumps with cardiovascular disease: The

Japan Collaborative Cohort (JACC) study. Atherosclerosis

241 (2015): 682-686.

29. Montella M, Dal Maso L, Crispo A, et al. Do childhood

diseases affect NHL and HL risk? A case-control study

from northern and southern Italy. Leukemia Research 30

(2006): 917-922.

30. Rosenlund H, Bergström A, Alm JS, et al. Allergic

disease and atopic sensitization in children in relation to

measles vaccination and measles infection. Pediatrics 123

(2009): 771-778.

31. Shaheen SO, Barker DJP, Heyes CB, et al. Measles and

atopy in Guinea-Bissau. The Lancet 347 (1996): 1792-

1796.

32. Benn CS, Amenyogbe N, Björkman A, et al. Implications

of non-specific effects for testing, approving, and

regulating vaccines. Drug Safety 46 (2023): 439-448.

33. Demicheli V, Rivetti A, Debalini MG, et al. Vaccines for

measles, mumps and rubella in children. Evidence‐Based

Child Health: A Cochrane Review Journal 8 (2013):

2076-2238.

34. Miller NZ. Vaccines and sudden infant death: An analysis

of the VAERS database 1990–2019 and review of the

medical literature. Toxicology Reports 8 (2021): 1324-

1335.

35. Centers for Disease Control and Prevention (CDC). CDC

vaccine safety. 2024. Autism and Vaccines. (2024).

36.Board on Health Promotion, Disease Prevention, &

Immunization Safety Review Committee. (2004).

Immunization safety review: Vaccines and autism.

Washington (DC): National Academies Press (US).

(2004).

37.Committee to Review Adverse Effects of Vaccines;

Institute of Medicine. Adverse effects of vaccines:

Evidence and causality. Clayton, E. W., Rusch, E.,

Ford, A., & Stratton, K. (Eds.). (2012). Adverse effects

of vaccines: Evidence and causality. Washington (DC):

National Academies Press (US). (2012).

38. Board on Population Health, Public Health Practice,

& Committee on the Assessment of Studies of Health

Outcomes Related to the Recommended Childhood

Immunization Schedule. (2013). The childhood

immunization schedule and safety: Stakeholder concerns,

scientific evidence, and future studies. Washington (DC):

National Academies Press (US). (2013).

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2134

39. Wakefield AJ, Murch SH, Anthony A, et al. RETRACTED:

Ileal-lymphoid-nodular hyperplasia, non-specific colitis,

and pervasive developmental disorder in children. The

Lancet 351 (1998): 637-641.

40. Murch SH, Anthony A, Casson DH, et al. Retraction of

an interpretation. The Lancet 363 (2004): 750.

41. Deer B. Wakefield’s “autistic enterocolitis” under the

microscope. BMJ (2010): 340.

42. Deer B. How the vaccine crisis was meant to make money.

BMJ (2011): 342.

43. Deer B. How the case against the MMR vaccine was

fixed. BMJ (2011): 342.

44. Ekbom A, Adami HO, Wakefield A, et al. Perinatal

measles infection and subsequent Crohn's disease. The

Lancet 344 (1994): 508-510.

45. Wakefield AJ, Ekbom A, Dhillon AP, et al. Crohn's

disease: Pathogenesis and persistent measles virus

infection. Gastroenterology 108 (1995): 911-916.

46. Ekbom A, Daszak P, Kraaz W, et al. Crohn's disease after

in-utero measles virus exposure. The Lancet 348 (1996):

515-517.

47. Thompson NP, Pounder RE, Wakefield AJ, et al. Is

measles vaccination a risk factor for inflammatory bowel

disease? The Lancet 345 (1995): 1071-1074.

48. Wakefield AJ, Puleston JM, Montgomery SM, et al. The

concept of entero‐colonic encephalopathy, autism and

opioid receptor ligands. Alimentary Pharmacology &

Therapeutics 16 (2002): 663-674.

49. Wakefield AJ, Ashwood P, ollins, I. The gut-brain axis in

childhood developmental disorders: Viruses and vaccines.

Neuropsychiatric Disorders & Infection (2005): 198.

50. Varia J, Herbert M, Hooker B. The neuroimmunology of

autism. (2024).

51. Turville C, Golden I. Autism and vaccination: The value

of the evidence base of a recent meta-analysis. Vaccine 33

(2015): 5494-5496.

52. Buie T, Campbell DB, Fuchs IIIGJ, et al. Evaluation,

diagnosis, and treatment of gastrointestinal disorders in

individuals with ASD: A consensus report. Pediatrics 125

(2010): S1-S18.

53. Casiday RE. Children's health and the social theory of

risk: Insights from the British measles, mumps and

rubella (MMR) controversy. Social Science & Medicine

65 (2007): 1059-1070.

54. Shapiro D, Hayburn A. Medical gaslighting as a

mechanism for medical trauma: Case studies and analysis.

Current Psychology (2024): 1-14.

55. Williams SJ, Calnan M. The ‘limits’ of medicalization?

Modern medicine and the lay populace in ‘late’ modernity.

Social Science & Medicine 42 (1996): 1609-1620.

56. Bennett P, Celik F, Winstanley J, et al. Living with vaccine-

induced immune thrombocytopenia and thrombosis: A

qualitative study. BMJ Open 13 (2023): e072658.

57. Fagen JL, Shelton JA, Luché-Thayer J. Medical

gaslighting and Lyme disease: The patient experience. In

Healthcare 12 (2023): 78.

58. Leach M. MMR mobilisation: Citizens and science in a

British vaccine controversy. The Institute of Development

Studies & Partner Organizations (2005).

59. Angell M. Drug companies & doctors: A story of

corruption. The New York Review of Books 56 (2009):

8-12.

60. Mello MM, Abiola S, Colgrove J. Pharmaceutical

companies’ role in state vaccination policymaking: The

case of human papillomavirus vaccination. American

Journal of Public Health 102 (2012): 893-898.

61. Lewis DL. Apparent egregious ethical misconduct

by British Medical Journal, Brian Deer. UK Research

Integrity Office (UKRIO), Reference (2012): (2011-060).

62. Sharav V. L’Affaire Wakefield: Shades of Dreyfus and

BMJ’s descent into tabloid science. Alliance for Human

Research Protection. (2017).

63. Mohammed SA, Rajashekar S, Ravindran SG, et al. Does

vaccination increase the risk of autism spectrum disorder?

Cureus, 14 (2022).

64. Turville C, Golden I. Autism and vaccination: The value

of the evidence base of a recent meta-analysis. Vaccine 33

(2015): 5494-5496.

65. Poltorak M, Leach M, Fairhead J, et al. ‘MMR talk’ and

vaccination choices: An ethnographic study in Brighton.

Social Science & Medicine 61 (2005): 709-719.

66. Hviid A, Hansen JV, Frisch M, et al. Measles, mumps,

rubella vaccination and autism: a nationwide cohort

study. Annals of Internal Medicine 170 (2019): 513-520.

67. Jenco MAAP News. Study: MMR vaccine not linked to

increased autism risk.

68. Bracho-Sanchez E. CNN. MMR vaccine does not cause

autism, another study confirms. (2019).

69. Stein RNPR. A large study provides more evidence that

MMR vaccines don’t cause autism. (2019).

70. Geggel L. Live Science. Confirmed: No link between

autism and measles vaccine, even for “at risk” kids.

(2019).

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2135

71. Hoffman J. New York Times. One more time, with big

data: Measles vaccine doesn’t cause autism. (2019).

72. Mammoser G. Healthline. Another massive study finds

measles vaccine doesn’t cause autism. (2024).

73. MedicalNewsToday. Transcripts. MMR vaccine does not

cause autism, even in those most at risk. (2019).

74. May B. Psychiatry Advisor. Study again confirms no link

between MMR vaccine and autism. (2019).

75. Paumgarten N. The New Yorker. The message of measles.

(2019).

76. Madsen KM, Hviid A, Vestergaard M, et al. A population-

based study of measles, mumps, and rubella vaccination

and autism. New England Journal of Medicine 347

(2002): 1477-1482.

77. Parner ET, Schendel DE, Thorsen P. Autism prevalence

trends over time in Denmark: Changes in prevalence and

age at diagnosis. Archives of Pediatrics & Adolescent

Medicine 162 (2008): 1150-1156.

78. Kragh Andersen P, Pohar Perme M, van Houwelingen

HC, et al. Analysis of time‐to‐event for observational

studies: Guidance to the use of intensity models. Statistics

in Medicine 40 (2021): 185-211.

79. Benkeser D, Carone M, Gilbert PB. Improved estimation

of the cumulative incidence of rare outcomes. Statistics in

Medicine 37 (2018): 280-293.

80. Abd ElHafeez S, D’Arrigo G, Leonardis D, et al. Methods

to analyze time‐to‐event data: The cox regression analysis.

Oxidative Medicine & Cellular Longevity 2021 (2021):

1302811.

81. Jain A, Marshall J, Buikema A, et al. Autism occurrence

by MMR vaccine status among US children with older

siblings with and without autism. JAMA 313 (2015):

1534-1540.

82. Betancur C. Etiological heterogeneity in autism spectrum

disorders: More than 100 genetic and genomic disorders

and still counting. Brain Research 1380 (2011): 42-77.

83. Hallmayer J, Cleveland S, Torres A, et al. Genetic

heritability and shared environmental factors among twin

pairs with autism. Archives of General Psychiatry 68

(2011): 1095-1102.

84. Gaugler T, Klei L, Sanders SJ, et al. Most genetic risk for

autism resides with common variation. Nature Genetics

46 (2014): 881-885.

85. Hocking MC, Albee MV, Kim M, et al. Social challenges,

autism spectrum disorder, and attention deficit/

hyperactivity disorder in youth with neurofibromatosis

type I. Applied Neuropsychology: Child (2024): 1-9.

86. Wiznitzer M. Autism and tuberous sclerosis. Journal of

Child Neurology 19 (2004): 675-679.

87. Peters SU, Beaudet AL, Madduri N, et al. Autism in

Angelman syndrome: Implications for autism research.

Clinical Genetics 66 (2004): 530-536.

88. Abbeduto L, McDuffie A, Thurman AJ. The fragile X

syndrome–autism comorbidity: What do we really know?

Frontiers in Genetics 5 (2014): 355.

89. Bennett JA, Germani T, Haqq AM, et al. Autism spectrum

disorder in Prader–Willi syndrome: A systematic review.

American Journal of Medical Genetics Part A 167 (2015):

2936-2944.

90. Reilly C. Autism spectrum disorders in Down syndrome:

A review. Research in Autism Spectrum Disorders 3

(2009): 829-839.

91. Vorstman JA, Morcus ME, Duijff SN, et al. The 22q11.

2 deletion in children: high rate of autistic disorders

and early onset of psychotic symptoms. Journal of the

American Academy of Child & Adolescent Psychiatry 45

(2006): 1104-1113.

92. Bjørklund G, Mkhitaryan M, Sahakyan E, et al. Linking

environmental chemicals to neuroinflammation and

autism spectrum disorder: Mechanisms and implications

for prevention. Molecular Neurobiology (2024): 1-13.

93. Park SK, Tao Y, Meeker JD, et al. Environmental

risk score as a new tool to examine multi-pollutants in

epidemiologic research: an example from the NHANES

study using serum lipid levels. PloS One 9 (2014): e98632.

94. Liu J, Lewis G. Environmental toxicity and poor cognitive

outcomes in children and adults. Journal of Environmental

Health 76 (2014): 130.

95. Maitre L, Bustamante M, Hernández-Ferrer C, et al.

Multi-omics signatures of the human early life exposome.

Nature Communications 13 (2022): 7024.

96. Palmer RF, Kattari D, Rincon R, et al. Assessing

chemical intolerance in parents predicts the risk of autism

and ADHD in their children. Journal of Xenobiotics 14

(2024): 350-367.

97. Merriam-Webster. Definition of the verb “lie”, meaning

number two. (2024).

98. Glickman G, Harrison E, Dobkins K. Vaccination rates

among younger siblings of children with autism. New

England Journal of Medicine 377 (2017): 1099-1101.

99. Zerbo O, Modaressi S, Goddard K, et al. Vaccination

patterns in children after autism spectrum disorder

diagnosis and in their younger siblings. JAMA Pediatrics

172 (2018): 469-475.

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2136

100. Kuwaik GA, Roberts W, Zwaigenbaum L, et al.

Immunization uptake in younger siblings of children

with autism spectrum disorder. Autism 18 (2014): 148-

155.

101. Jain A, Marshall J, Buikema A, et al. Autism occurrence

by MMR vaccine status among US children with older

siblings with and without autism. JAMA 313 (2015):

1534-1540.

102. European Centre for Disease Prevention and Control

(ECDC). ECDC vaccine scheduler. Denmark:

Recommended vaccinations. (2024).

103. Statens Serum Institut. Danish childhood vaccination

program vaccination offers protection. 13th ed.

Sundhedsstyrelsen. (2024).

104. Ingels H, Rasmussen J, Andersen PH, et al. Impact

of pneumococcal vaccination in Denmark during the

first 3 years after PCV introduction in the childhood

immunization programme. Vaccine 30 (2012): 3944-

3950.

105. Harboe ZB, Dalby T, Weinberger DM, et al. Impact

of 13-valent pneumococcal conjugate vaccination in

invasive pneumococcal disease incidence and mortality.

Clinical Infectious Diseases 59 (2014): 1066-1073.

106. Wójcik OP, Simonsen J, Mølbak K, et al. Validation

of the 5-year tetanus, diphtheria, pertussis and polio

booster vaccination in the Danish childhood vaccination

database. Vaccine 31 (2013): 955-959.

107. Harder KM, Cowan S, Eriksen MB, et al. Universal

screening for hepatitis B among pregnant women led to

96% vaccination coverage among newborns of HBsAg

positive mothers in Denmark. Vaccine 29 (2011): 9303-

9307.

108. Centers for Disease Control and Prevention (CDC).

CDC Vaccines & immunizations. Recommended

immunization schedule for persons age 0 through 18

years. (2013).

109. US Food and Drug Administration (FDA). (2023).
110. World Health Organization (WHO). WHO International.

Human papillomavirus (HPV). (2018).

111. Statens Serum Institut. Vaccination against cervical

cancer (HPV). (2018).

112. Turville C, Golden I. Autism and vaccination: The value

of the evidence base of a recent meta-analysis. Vaccine

33 (2015): 5494-5496.

113. Sorup S, Jensen AK, Aaby P, et al. Revaccination with

measles-mumps-rubella vaccine and infectious disease

morbidity: A Danish register-based cohort study.

Clinical Infectious Diseases 68 (2019): 282-290.

114. Sorup S, Jensen AK, Aaby P, et al. Revaccination with

measles-mumps-rubella vaccine and infectious disease

morbidity: A Danish register-based cohort study.

Clinical Infectious Diseases 68 (2019): 282-290.

115. Davidkin I, Peltola H, Leinikki P, et al. Duration of

rubella immunity induced by two-dose measles, mumps

and rubella (MMR) vaccination. A 15-year follow-up in

Finland. Vaccine 18 (2000): 3106-3112.

116. Paunio M, Heinonen OP, Virtanen M, et al. Measles

history and atopic diseases: A population-based cross-

sectional study. JAMA 283 (2000): 343-346.

117. US Food and Drug Administration (FDA). U.S. Food

& Drug Administration (FDA). GlaxoSmithKline

Biologicals SA, Priorix Package Insert. (2022).

118. Sorup S, Jensen AK, Aaby P, et al. Revaccination with

measles-mumps-rubella vaccine and infectious disease

morbidity: A Danish register-based cohort study.

Clinical Infectious Diseases 68 (2019): 282-290.

119. Gillet Y, Habermehl P, Thomas S, et al. Immunogenicity

and safety of concomitant administration of a measles,

mumps and rubella vaccine (MM-RvaxPro®) and a

varicella vaccine (VARIVAX®) by intramuscular

or subcutaneous routes at separate injection sites: A

randomised clinical trial. BMC Medicine 7 (2009): 1-11.

120. European Commission. Sanofi Pasteur, M-M-

RVAXPRO Package Insert. (2024).

121. Statens Serum Institut. Uge 24 – 2013. (2024).
122. Benn CS. (MD, PhD) Chair of Health Sciences,

Department of Clinical Research, Danish Institute

for Advanced Study (DIAS) University of Southern

Denmark (2024).

123. Statens Serum Institut. Pneumokokvaccine I Det Danske

Børnevaccinationsprogram. (2008).

124. Parner ET, Schendel DE, Thorsen P. Autism prevalence

trends over time in Denmark: Changes in prevalence and

age at diagnosis. Archives of Pediatrics & Adolescent

Medicine 162 (2008): 1150-1156.

125. Statens Serum Institut. MMR 2 Vaccination Advanced

to 4 Years. (2008).

126. Knuesel I, Chicha L, Britschgi M, et al. Maternal

immune activation and abnormal brain development

across CNS disorders. Nature Reviews Neurology 10

(2014): 643-660.

127. Wu WL, Hsiao EY, Yan Z, et al. The placental

interleukin-6 signaling controls fetal brain development

and behavior. Brain, Behavior, & Immunity 62 (2017):

11-23.

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2137

128. Zerbo O, Qian Y, Yoshida C, et al. Association between

influenza infection and vaccination during pregnancy

and risk of autism spectrum disorder. JAMA Pediatrics

171 (2017): e163609-e163609.

129. Hooker BS. Influenza vaccination in the first trimester of

pregnancy and risk of autism spectrum disorder. JAMA

Pediatrics 171 (2017): 600-600.

130. Jorgensen P, Mereckiene J, Cotter S, et al. How close

are countries of the WHO European Region to achieving

the goal of vaccinating 75% of key risk groups against

influenza? Results from national surveys on seasonal

influenza vaccination programmes, 2008/2009 to

2014/2015. Vaccine 36 (2018): 442-452.

131. Molgaard‐Nielsen D, Fischer TK, Krause TG, et al.

Effectiveness of maternal immunization with trivalent

inactivated influenza vaccine in pregnant women and

their infants. Journal of Internal Medicine 286 (2019):

469-480.

132. Nakken CS, Skovdal M, Nellums LB, et al. Vaccination

status and needs of asylum-seeking children in Denmark:

A retrospective data analysis. Public Health 158 (2018):

110-116.

133. Cherri Z, Lau K, Nellums LB, et al. The immune status

of migrant populations in Europe and implications

for vaccine-preventable disease control: A systematic

review and meta-analysis. Journal of Travel Medicine,

taae033. (2024).

134. Holt N, Mygind A, Bro F. Danish MMR vaccination

coverage is considerably higher than reported. Danish

Medical Journal 64 (2017): A5345.

135. Schendel DE, Thorsteinsson E. Cumulative incidence

of autism into adulthood for birth cohorts in Denmark,

1980-2012. JAMA 320 (2018): 1811-1813.

136. Centers for Disease Control and Prevention (CDC).

About Autism Spectrum Disorder (ASD). Data and

Statistics on Autism Spectrum Disorder. (2024).

137. Munafò MR, Nosek BA, Bishop DV, et al. A manifesto

for reproducible science. Nature Human Behavior 1

(2017): 1-9.

138. Clarkson E (PhD), Chief Statistician at the National

Institute for Aviation Research (NIAR) and Senior

Research Engineer and Chief Statistician for the National

Center for Advanced Materials Performance (NCAMP).

Wichita State University (2019).

139. Centers for Disease Control and Prevention (CDC). CDC

Vaccines & Immunizations. 2023. Child and Adolescent

Immunization Schedule by Age. (2023).

140. Centers for Disease Control and Prevention (CDC). CDC

Pregnancy and Vaccination. Vaccine recommendations

before, during, and after pregnancy. (2024).

141. Bennett J. Shortcomings in the latest MMR vaccination

and autism study: A healthcare administrator’s response.

Science, Public Health Policy & the Law 1 (2019):

2019-2024.

142. BioSpace. Biologics market size to hit around USD 1.37

trillion by 2033. (2024).

143. Precedence Research. Vaccines market size, share, and

trends 2024 to 2034. (2024).

144. Allied Market Research. Mumps vaccine market

size, share, competitive landscape and trend analysis

report, by age group, by distribution channel: Global

opportunity analysis and Industry Forecast 2021-2031.

(2022).

145. Parker EM, Zhu BP, Li Z, et al. Domains of excellence:

A CDC framework for developing high-quality, impact-

driven public health science publications. Journal of

Public Health Management & Practice 30 (2024): 72-78.

146. Kern JK, Geier DA, Deth RC, et al. Systematic

assessment of research on autism spectrum disorder

(ASD) and mercury reveals conflicts of interest and the

need for transparency in autism research. Science &

Engineering Ethics 23 (2017): 1691-1718.

147. Lenzer J. Centers for Disease Control and Prevention:

Protecting the private good? BMJ 350 (2015).

148. Huntoon LR. CDC: Bias and disturbing conflicts of

interest. Journal of American Physicians & Surgeons 23

(2020): 66-69.

149. Miller NZ, Goldman GS. Case study: Varicella vaccine

and the suppression of data. Journal of American

Physicians and Surgeons 27 (2022).

150. Hooker BS. Reanalysis of CDC data on autism incidence

and time of first MMR vaccination. Journal of American

Physicians & Surgeons 23 (2018): 105-110.

151. Hooker BS. CDC data manipulation exposed: Four years

later. Journal of American Physicians & Surgeons 22

(2017): 119-121.

152. Nissen SE. Conflicts of interest and professional medical

associations: Progress and remaining challenges. JAMA

317 (2017): 1737-1738.

153. Deirdre I. Fox News. Conflict of children’s interest

inside the American academy of pediatrics. (2010).

154. Steinbrook R, Kassirer JP, Angell M. Justifying conflicts

of interest in medical journals: A very bad idea. BMJ

350 (2015).

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2138

155. Angell M, Relman A. S. New York Times. Physicians,

educate yourselves. (2004).

156. Angell M. Drug companies & doctors: A story of

corruption. The New York Review of Books 56 (2009):

8-12.

157. Statens Serum Institut. Vaccine research. (2022).
158. Statens Serum Institut. No Association between MMR

vaccine and autism. (2019).

159. Novo Nordisk Foundation. Who are we? (2024) .
160. International Committee of Medical Journal Editors.

ICMJE Form for disclosure of potential conflicts of

interest. (2019).

161. Indenrigs-OG Sundhedsministeriet. Minister for the

interior and health of Denmark. (2022).

162. Novo Nordisk Foundation. Ownership. (2022).
163. Novo Nordisk A/S. Corporate governance. (2024).
164. CompaniesMarketCap. Global ranking. Market

capitalization of Novo Nordisk (NVO). (2024).

165. Novo Holdings. Corporate governance. (2024).
166. Novo Holdings. Investments. (2021).
167. Novo Holdings. Joining the fight against COVID-19

while running a life-saving business. (2021).

168. Novo Nordisk Foundation Initiative for Vaccines and

Immunity (NIVI). Projekter og initiativer. (2023).

169. University of Copenhagen. New initiative puts Danish

vaccine science on the global map. (2023).

170. NIVI Novo Nordisk Foundation Initiative for Vaccines

and Immunity. About the initiative. (2024).

171. Novo Nordisk Foundation. The Novo Nordisk

Foundation Vaccine Accelerator (NVAC). (2024).

172. Statens Serum Institut. Vaccination against cervical

cancer (HPV). (2018).

173. Olsen SF, Halldorsson TI, Thorne-Lyman AL, et al.

Plasma concentrations of long chain N-3 fatty acids in

early and mid-pregnancy and risk of early preterm birth.

EBioMedicine 35 (2018): 325-333.

174. Novo Nordisk Foundation. The Novo Nordisk

Foundation awards grants to 12 excellent research

leaders within bioscience and basic biomedicine. (2019).

175. Statens Serum Institut. New research sheds light on

genetics of placenta growth. (2023).

176. Statens Serum Institut. SSI researcher receives multi-

million kroner grant from the Novo Nordisk Foundation.

(2024).

177. Statens Serum Institut. Babies’ own genes influence

when they are born. (2024).

178. Statens Serum Institut. The Danish national biobank.

(2023).

179. Angell M, Relman AS. Patents, profits & American

medicine: Conflicts of interest in the testing & marketing

of new drugs. Daedalus 131 (2002): 102-111.

180 Kennedy Jr RF. Thimerosal: Let the science speak:

The evidence supporting the immediate removal of

mercury—A known neurotoxin-From vaccines. Simon

& Schuster. (2015).

181. Schuemie MJ, Hripcsak G, Ryan PB, et al. Empirical

confidence interval calibration for population-level

effect estimation studies in observational healthcare

data. Proceedings of the National Academy of Sciences

115 (2018): 2571-2577.

182. Hviid A, Stellfeld M, Wohlfahrt J, et al. Association

between thimerosal-containing vaccine and autism.

JAMA 290 (2003): 1763-1766.

183. Hviid A, Stellfeld M, Wohlfahrt J, et al. Childhood

vaccination and type 1 diabetes. New England Journal

of Medicine, 350 (2004): 1398-1404.

184. Vestergaard M, Hviid A, Madsen KM, et al. MMR

vaccination and febrile seizures: Evaluation of

susceptible subgroups and long-term prognosis. JAMA

292 (2004): 351-357.

185. Hviid A, Melbye M, Pasternak B. Use of selective

serotonin reuptake inhibitors during pregnancy and

risk of autism. New England Journal of Medicine 369

(2013): 2406-2415.

186. Pasternak B, Svanström H, Hviid A. Ondansetron in

pregnancy and risk of adverse fetal outcomes. New

England Journal of Medicine 368 (2013): 814-823.

187. Geier DA, King PG, Hooker BS, et al. Thimerosal:

Clinical, epidemiologic and biochemical studies. Clinica

Chimica acta 444 (2015): 212-220.

188. Kern J, Geier D, Audhya T, et al. Evidence of parallels

between mercury intoxication and the brain pathology in

autism. Acta Neurobiologiae Experimentalis 72 (2012):

113-153.

189. Mezzacappa A, Lasica PA, Gianfagna F, et al. Risk

for autism spectrum disorders according to period of

prenatal antidepressant exposure: A systematic review

and meta-analysis. JAMA Pediatrics 171 (2017): 555-

563.

190. Kennedy D. Ondansetron and pregnancy: Understanding

the data. Obstetric Medicine 9 (2016): 28-33.

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2139

191. Kirby D. The vaccine-autism court document every

American should read. Huffington Post. (2008).

192. Transcripts. Unraveling the mystery of autism; talking

with the CDC director; stories of children with autism;

aging with autism. (2008).

193. Reuters. Reuters. Former CDC head lands vaccine job

at Merck. (2009).

194. Merck. Dr. Julie L. Gerberding to Retire from Merck.

(2022).

195. Hallmayer J, Cleveland S, Torres A, et al. Genetic

heritability and shared environmental factors among

twin pairs with autism. Archives of General Psychiatry

68 (2011): 1095-1102.

196. Bradstreet J. Biological evidence of significant vaccine

related side-effects resulting in neurodevelopmental

disorders. Presentation to the Vaccine Safety Committee

of the Institute of Medicine, The National Academies of

Science 9 (2004)..

197. Maitre L, Bustamante M, Hernández-Ferrer C, et
198. Multi-omics signatures of the human early life

exposome. Nature Communications 13 (2022): 7024.

198. Laugesen K, Mengel-From J, Christensen K, et al. A

review of major Danish biobanks: Advantages and

possibilities of health research in Denmark. Clinical

Epidemiology (2023): 213-239.

199. Attkisson S. CDC: “Possibility” that vaccines rarely

trigger autism. (2018).

200. Price CS, Thompson WW, Goodson B, et al. Prenatal

and infant exposure to thimerosal from vaccines and

immunoglobulins and risk of autism. Pediatrics 126

(2010): 656-664.

201. Janiaud P, Agarwal A, Tzoulaki I, et al. Validity of

observational evidence on putative risk and protective

factors: appraisal of 3744 meta-analyses on 57 topics.

BMC Medicine 19 (2021): 1-17.

202. Ioannidis JP. Why most clinical research is not useful.

PLoS medicine 13 (2016): e1002049.

203. Kennedy RF, Hooker B. Vax-Unvax: Let the science

speak. Skyhorse Publishing. (2023).

204. Chandler J, Cumpston M, Li T, et al. Cochrane handbook

for systematic reviews of interventions. Hoboken, Wiley

(2019).

205. Barnes HJ, Ragnarsson G, Alván G. Quality and safety

considerations for recombinant biological medicines: A

regulatory perspective. International Journal of Risk &

Safety in Medicine 21 (2009): 13-22.

206. Valiant WG, Cai K, Vallone PM. A history of adventitious

agent contamination and the current methods to detect

and remove them from pharmaceutical products.

Biologicals 80 (2022): 6-17.

207. Chooi WH, Ng PW, Hussain Z, et al. Vaccine

contamination: Causes and control. Vaccine 40 (2022):

1699.

208. Aranha H, Solutions CP. Virus safety of

biopharmaceuticals. Contract Pharma 13 (2011).

209. English JM. The rights and wrongs of measles

vaccination. British Homoeopathic Journal 84 (1995):

156-163.

210. Price D, Jefferson T, Demicheli V. Methodological

issues arising from systematic reviews of the evidence

of safety of vaccines. Vaccine 22 (2004): 2080-2084.

211. Halvorsen R. The Truth About Vaccines: How we are

used as guinea pigs without knowing it. Gibson Square.

(2007).

212. McKinlay JB, McKinlay SM. The questionable

contribution of medical measures to the decline of

mortality in the United States in the twentieth century.

The Milbank Memorial Fund Quarterly. Health &

Society (1977): 405-428.

213. Armstrong GL, Conn LA, Pinner RW. Trends in

infectious disease mortality in the United States during

the 20th century. JAMA 281 (1999): 61-66.

214. Beck MA. The role of nutrition in viral disease. The

Journal of Nutritional Biochemistry 7 (1996): 683-690.

215. Hooker BS, Miller NZ. Analysis of health outcomes in

vaccinated and unvaccinated children: Developmental

delays, asthma, ear infections and gastrointestinal

disorders. SAGE Open Medicine 8 (2020):

2050312120925344.

216. Miller NZ, Goldman GS. Neonatal, infant, and under age

five vaccine doses routinely given in developed nations

and their association with mortality rates. Cureus 15

(2023).

217. Light DW, Lexchin J, Darrow JJ. Institutional corruption

of pharmaceuticals and the myth of safe and effective

drugs. Journal of Law, Medicine & Ethics 41 (2013):

590-600.

218. Barosi G, Gale RP. Is there expert consensus on expert

consensus? Bone Marrow Transplantation 53 (2018):

1055-1060.

219. Djulbegovic B, Guyatt G. Evidence vs consensus in

clinical practice guidelines. JAMA 322 (2019): 725-726.

220. Bragazzi NL, Watad A, Amital H, et al. Debate on

vaccines and autoimmunity: Do not attack the author,

Hammond JR, et al., J Biotechnol Biomed 2025

DOI:10.26502/jbb.2642-91280185

Citation: Jeremy R Hammond, Jeet Varia, Brian Hooker. Hviid et al. 2019 Vaccine-Autism Study: Much Ado About Nothing?. Journal of

Biotechnology and Biomedicine. 8 (2025): 118-140.

Volume 8 • Issue 2140

yet discuss it methodologically. Vaccine 35 (2017):

5522-5526.

221. Martin B. On the suppression of vaccination dissent.

Science & Engineering Ethics 21 (2015): 143-157.

222. Elisha E, Guetzkow J, Shir-Raz Y, et al. Suppressing

scientific discourse on vaccines? Self-perceptions of

researchers and practitioners. In Hec Forum 36 (2024):

71-89.

223. Kempner J. The chilling effect: how do researchers react

to controversy? PLoS Medicine 5 (2008): e222.

224. Martin B. The scientific straightjacket: The power

structure of science and the suppression of environmental

scholarship. Ecologist 11 (1981): 33-43.

225. Larsson A, Oxman AD, Carling C, et al. Medical

messages in the media–barriers and solutions to

improving medical journalism. Health Expectations 6

(2003): 323-331.

226. Shuchman M, Wilkes MS. Medical scientists and health

news reporting: A case of miscommunication. Annals of

Internal Medicine 126 (1997): 976-982.

227. Carroll AE. New York Times. Why it’s still worth

getting a flu shot. (2018).

228. Carroll AE New York Times. A link between alcohol

and cancer? It’s not nearly as scary as it seems. (2017).

229. Lipworth W, Kerridge I, Morrell B, et al. Medicine, the

media and political interests. Journal of Medical Ethics

38 (2012): 768-770.

230. Wiley KE, Leask J, Attwell K, et al. Stigmatized for

standing up for my child: A qualitative study of non-

vaccinating parents in Australia. SSM-population Health

16 (2021): 100926.

231. Kennedy Jr, RF. Profiles of the vaccine-injured: "A

lifetime price to pay." Simon & Schuster. (2022).

This article is an open access article distributed under the terms and conditions of the

Creative Commons Attribution (CC-BY) license 4.0