“You’ve taken two studies for which different doses were used and come up with a composite that doesn’t represent either of the doses," an expert said.
LONDON — AstraZeneca and Oxford University on Wednesday acknowledged a manufacturing error that has raised questions about their Covid-19 vaccine after revealing earlier this week it was “highly effective” against the disease.
On Monday, researchers said AstraZeneca vaccine had an efficacy of up to 90 percent when half a dose was administered followed by a full dose. That efficacy rate is on par with other vaccine candidates announced by Pfizer and Moderna earlier this month. In the group that got two full doses, the vaccine appeared to be 62 percent effective. Combined, the drugmakers said the vaccine appeared to be 70 percent effective.