DTP-Vaccinated African Infants Had a Higher Death Rate than Unvaccinated Infants, According to New “vax/unvax” Study
A study published earlier this month (see HERE ) examining the effect of vaccination on mortality in 3-5 month old infants in the West African nation of Guinea-Bissau showed a fivefold higher death rates in infants who received diphtheria-tetanus-pertussis (DTP) and oral polio (OPV) vaccines compared to unvaccinated infants. The study, published in the journal EBioMedicine by Danish researchers from the Statens Serum Institut (SSI), was based on infants born between 1980 and 1983 and used data collected by the SSI’s Bandim Health Project (BHP). The study of vaccinated and unvaccinated African infants represents a rare, albeit limited, example of the kind of “vaxxed/unvaxxed’ study that many critics of American vaccination policy have long called for.
In their prospective study of over 1,000 infants, the SSI authors examined the effects on infant mortality of a new vaccination program that included both OPV and DTP vaccines. They reserved their harshest assessment for the newly introduced DTP vaccine, observing pointedly that “DTP was associated with 5-fold higher mortality than being unvaccinated. No prospective study has shown beneficial survival effects of DTP.”
In a broader criticism of global vaccine policy, the authors continued, “Unfortunately, DTP is the most widely used vaccine, and the proportion who receives DTP3 [three doses of the DTP vaccine] is used globally as an indicator of the performance of national vaccination programs.” In a further criticism of DTP vaccines, the analysis suggests that the OPV, which was typically administered together with DTP vaccine, had a moderating effect on the death risk of DTP. When (due to logistical problems with OPV availability) infants were vaccinated with DTP only, the death rates were even worse: as much as ten times higher than unvaccinated infants.
Unlike the recently leaked “vax/unvaxxed” study on homeschool children (see HERE) and the more commonly understood usage today of the “vaxxed/unvaxxed” concept, this analysis was narrower. The study examined infants during a brief window of time—the period between 3 and 6 months of age--and measured a single outcome—death. Described by the authors as a “natural experiment,” the study was designed in order to address on ongoing debate over the efficacy in low-income countries of the Expanded Immunization Program (EPI) since its introduction in the 1970s. At the time, the EPI targeted countries like Guinea-Bissau that had high infant mortality rates--under-five mortality rates were close to 50% there in 1978-9—and included four vaccines for seven diseases. Since individual vaccines included in the EPI might have different effects, the authors decried the absence of “individually randomized studies,” noting that “surprisingly few studies examined the introduction of vaccines and their impact on child survival.”
Due to its specific focus, the study design has little to say about the vaccine schedule debate in high-income countries and has several key limitations. Most notably, the “unvaccinated” children in the BHP study group only remained unvaccinated for a period of less than 14 weeks between 3 and 6 months of age until they attended the “quarterly weighing sessions” when OPV and DTP vaccines were administered. Even this briefly unvaccinated group wasn’t fully unvaccinated. The authors noted that “of the 651 unvaccinated children, 219 received DTP and/or OPV before their first weighing examination. These children counted as ‘unvaccinated’ until their first weighing examination.” Even though the death rate in the unvaccinated group was lower than in the vaccinated group, death rates were high on both sides. Five of the eighteen deaths covered in the study period occurred in the unvaccinated group and the authors don’t disclose whether any of these deaths had received a vaccination before the official examination “landmarks” used to define vaccination events in the database.
Despite the unusual nature of their “natural experiment”, this new BHP paper does offer some useful information for developed world vaccination debate, in which many express concern over excessively aggressive vaccine schedules that mandate “too many, too soon”. In that debate, the question of designing alternative schedules based on different health benefits of individual vaccines has risen to the fore as a number of doctors have offered non-standard schedules that depart from officially sanctioned schedules of public health authorities like the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO).
Guinea-Bissau offers an opportunity for a natural experiment in vaxxed/unvaxxed science because the population there was largely unvaccinated until late in the 20th century. The BHP “took part in the introduction of vaccines” in Bandim starting in 1981; until the launch of the WHO’s Expanded Program on Immunization in that year, vaccination coverage in Guinea-Bissau was below 5%. The EPI schedule that was introduced in Bandim included several live attenuated vaccine strains: one dose of the BCG (tuberculosis) vaccine at birth, three doses of OPV starting at 3 months and one dose of measles vaccine after 9 months. In addition, three doses of the DTP vaccine, with its three inactivated bacterial components, were given along with the OPV starting at 3 months. Since “the disease protective effects [of the EPI] were well documented,” the BHP authors said, little effort went into studying the overall health effects of the program as a whole. Instead, “the main issue was at which age to introduce the [individual] vaccine most effectively.”
Dr. Peter Aaby, the senior author on this month’s paper, has long made the case for assessing the broad health effects of individual vaccines. Aaby founded the BHP in 1978 and has observed vaccination programs in Africa for decades since. He has argued for some time that there is a distinction between the health effects of live attenuated and inactivated vaccines. Aaby has argued for instance, that the health benefits of measles vaccination (an attenuated live virus) go beyond the prevention of deaths associated with acute measles infection. By contrast, Aaby has argued that DTP vaccines have had no such broad benefit. In this most recent study, he makes the case against DTP even more strongly, demonstrating that DTP vaccines sharply increased death rates in African infants.
Aaby’s theory that the “non-specific effects” (NSEs) of vaccination outweigh their effect on disease prevention suggests a more nuanced view of vaccination schedules than the simple “pro-vaccine vs anti-vaccine” controversy touted in most media coverage of the vaccine debate. If different vaccines can have opposing non-specific effects, then the net benefits of an overall schedule would require close monitoring and the detailed design of vaccine schedules would be a subject for policy debate rather than the all-or-nothing stance of many public health officials. In their recent paper, the BHP authors offer support for the need to assess the health effects of the entire EPI schedule rather than the disease protection effects of individual vaccines. Despite past BHP publications providing evidence for beneficial NSEs of the measles vaccines contained in the EPI introduced in Guinea-Bissau, the overall health outcomes that ensued following the EPI’s introduction were negative. In their new paper, the BHP authors showed that infant death rates following the new vaccine program introduction more than doubled, going from 4.7 per 100 person-years in 1980 to 12.1 in 1983.
Harsh criticism of one of the foundational pieces of the modern immunization schedule is notable when it comes from an insider like Dr. Aaby. His conclusion that “all currently available evidence suggests that DTP vaccine may kill more children from other causes than it saves from diphtheria, tetanus or pertussis” is an urgent call for action from the WHO.
Mark Blaxill is Editor-At-Large for Age of Autism.