Astrazeneca revises vaccine’s efficacy rate

Updated analysis follows challenges to earlier report.

An updated company analysis of the coronavirus vaccine developed by Astrazeneca and the University of Oxford showed that the twoshot regimen was robustly effective — 76% at preventing symptomatic illness, according to a news release from the drug maker late Wednesday.

The finding, only slightly lower than results announced days earlier, underscores that the vaccine being widely used by many countries appears to be a powerful tool to help end the pandemic. No severe cases of illness were reported in study volunteers who received the vaccine. Among people 65 and older, the vaccine was 85% effective, the company reported.

The new data may not resolve challenges that the vaccine and the company face in the United States, because repeated missteps have sown confusion and distrust that may result in slower and closer scrutiny.

Astrazeneca and Oxford’s announcement Monday that their vaccine was 79% effective in a 32,000-person trial in the U.S. buoyed the company’s stock price and impressed government officials. Then, late Monday, Data and Safety Monitoring Board, an independent data-monitoring committee, took the highly unusual step of writing to company and government officials airing concerns.

In the letter, obtained by The Washington Post, the committee revealed that after several meetings and requests for more recent data, the company had chosen to present earlier, now-outdated data to the world that cast its vaccine in the most favorable light.

The National Institutes of Health issued a statement early Tuesday, urging the company and data committee to work together to “ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”

ALVARO BARRIENTOS/AP FILE Astrazeneca now says its COVID-19 vaccine is 76% effective at preventing symptomatic illness, a slight change from its earlier boast.