AstraZeneca has released revised efficacy data from a Phase 3 clinical trial of its coronavirus vaccine after U.S. health officials questioned information that the company provided earlier this week.
In a news release Thursday, AstraZeneca said a primary analysis of the trial – which involved more than 32,000 participants in the United States, Peru and Chile – found that the two-dose vaccine was 76% effective at preventing symptomatic COVID-19. Additionally, the vaccine demonstrated 85% efficacy among participants age 65 and older, as well as “100% efficacy against severe or critical disease and hospitalization,” the release said.
“The vaccine was well-tolerated, and no safety concerns related to the vaccine were identified,” the company added.
The news came two days after U.S. health officials said AstraZeneca possibly “included outdated information” in a Monday press release, in which the company claimed an “interim analysis” found the vaccine 79% effective overall. In a statement early Tuesday, the U.S. National Institute of Allergy and Infectious Diseases publicly shared those concerns.
“Late Monday, the Data and Safety Monitoring Board (DSMB) notified NIAID, [the Biomedical Advanced Research and Development Authority] and AstraZeneca that it was concerned by information released by AstraZeneca on initial data from its COVID-19 vaccine clinical trial,” the statement read. “The DSMB expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data. We urge the company to work with the DSMB to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”
AstraZeneca responded that the numbers released Monday “were based on a pre-specified interim analysis with a data cutoff” of Feb. 17. The company added that it would “issue results of the primary analysis within 48 hours,” according to the statement.
Although dozens of countries have authorized AstraZeneca’s vaccine for emergency use, it has not yet been approved in the United States, according to the AP.
Several European countries, including Germany, Spain, France and Italy, recently agreed to resume administering the AstraZeneca vaccine after temporarily suspending its use because a small number of recipients had reported blood clots, The New York Times reported. After conducting a review, the European Medicines Agency last week deemed the shot safe but said the vaccine will now include a warning label, according to the newspaper.