AstraZeneca has released an updated estimate of how well its coronavirus vaccine works, two days after federal scientists accused the company of cherrypicking data included in a press release touting the results of the company’s Phase III U.S. trial.
The British drugmaker now says the vaccine is 76 percent effective against symptomatic Covid-19 infection, slightly lower than the 79 percent figure it released Monday. The estimated efficacy in people over 65 rose slightly, from 80 percent to 85 percent.
The latest analysis is based on 190 cases of infection among the nearly 33,000 people enrolled in the company’s late-stage U.S. study. AstraZeneca said there are 14 “additional possible or probable” infections among trial volunteers that are still be evaluated and could change the overall results slightly.
The company’s initial data release Monday was met hours later by a rare rebuke from the government’s Data Safety Monitoring Board, an independent group overseeing vaccine makers’ trials.
The group questioned why AstraZeneca used “outdated information” from an interim analysis of trial data in mid-February, rather than more up-to-date results showing slightly reduced, but still strong, efficacy, according to a late-night statement from the National Institute of Allergy and Infectious Diseases.
“The issue that the DSMB had is straightforward and very simple: The DSMB had data that they know the company had. When they saw the press release, they said, ‘wait a minute — the data in the press release do not reflect the most recent data that we know you have,'” NIAID Director Anthony Fauci said at the time.
AstraZeneca defended itself by saying the latest data were still “consistent” with what it had shared. While overall effectiveness ebbed slight down, efficacy in people 65 years old and over jumped from 80 to 85 percent. The company maintained Wednesday that its vaccine is 100 percent effective at preventing severe disease and hospitalization, mirroring its earlier announcement.
The latest results still place AstraZeneca well above the Food and Drug Administration’s bar for authorizing a coronavirus vaccine — 50 percent efficacy — for both adults overall and the elderly in particular. But the confusion has triggered worries that the public will lose confidence in the shot even as AstraZeneca is poised to deliver tens of millions of doses to the U.S. government. The company has said it plans to seek emergency authorization for its vaccine from the Food and Drug Administration by mid-April.
The U.S. furor comes less than a week after the European Medicines Agency rushed to assure member countries that the vaccine is safe and effective amid unsubstantiated fears that it caused blood clots, leading 13 countries to suspend its use.
AstraZeneca’s Wednesday update came in the form of a company press release, as did the Monday data — a practice that scientists have criticized during the pandemic because it provides an incomplete picture of trial results. AstraZeneca said it will publish its findings in a peer-reviewed scientific journal in the coming weeks.
“The primary analysis is consistent with our previously released interim analysis, and confirms that our COVID-19 vaccine is highly effective in adults, including those aged 65 years and over,” Mene Pangalos, EVP of BioPharmaceuticals R&D, said in a statement.
A spokesperson has said the company have 30 million doses on hand and could supply 50 million more in the coming weeks, plus 15 to 20 million each subsequent month.
The Trump administration inked a deal with AstraZeneca to supply 300 million doses of its vaccine.