AstraZeneca's COVID-19 vaccine defies data controversy with 76% effectiveness in phase 3

AstraZeneca released updated findings on its COVID-19 vaccine Thursday. (solarseven/iStock/Getty Images Plus)

AstraZeneca created a COVID-19 vaccine data controversy this week by reportedly selecting the most favorable data to tout on its program, a move independent data monitors publicly flagged in a middle-of-the-night missive. Now, with a speedy data update and analysis, AstraZeneca says it can “confirm” the vaccine’s phase 3 success.

In a newly released primary analysis, AstraZeneca says its vaccine was 76% effective against symptomatic COVID-19 and 85% effective against symptomatic disease in people 65 and over. The shot was also 100% effective against severe disease and hospitalization in the phase 3 trial.

The numbers are close to those AstraZeneca touted Monday morning. In an interim analysis of the vaccine data, AZ found the shot to be 79% effective against symptomatic COVID-19 and 100% effective against severe disease. 

But, in a highly unusual development later that night, the U.S. National Institute for Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, said the trial's independent data monitoring board had flagged “concerns” about the data AstraZeneca released. The NIAID statement touched off a firestorm of criticism from experts and amateur pharma watchers alike.

The NIAID said the drugmaker “may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data.” AstraZeneca responded that the data it released were “consistent” with its preliminary review of the forthcoming primary analysis. 

RELATED: AstraZeneca scrambles to update COVID-19 vaccine data after NIH flags 'concerns' about Monday's triumphant release 

The new data confirm “our COVID-19 vaccine is highly effective in adults, including those aged 65 years and over," AZ's executive vice president of biopharma R&D, Mene Pangalos, said in a statement. AstraZeneca plans an FDA emergency use authorization filing and will have millions of doses ready to ship if the regulator grants an approval. 

In all, the episode amounted to an “unforced error” on AstraZeneca’s part, President Joe Biden’s chief medical adviser Anthony Fauci, M.D., told "Good Morning America" earlier this week. Thursday, Ashish Jha, M.D., dean of the Brown University School of Public Health, tweeted it’s a “great vaccine” but that the company’s communications were “awful.” 

RELATED: Again? AstraZeneca faces vaccine PR problems as regulators push back on data and pundits shake their heads 

The new data are based on 190 cases in the primary analysis, AZ says. Another 14 cases are probable or possible, so the efficacy number could change slightly based on how many of those cases were in the vaccine group versus the placebo group.