U.S. health officials and an oversight board accused AstraZeneca of presenting potentially misleading information

Federal health officials and an independent oversight board accused AstraZeneca of presenting the world with potentially misleading information about the effectiveness of the company’s Covid-19 vaccine, an extraordinary blow to the credibility of a company whose product has been seen as critical to the global fight against the pandemic.

In a two-page letter to AstraZeneca and federal authorities on Monday, an independent panel of medical experts that was helping oversee the vaccine’s clinical trial in the United States said the company had essentially cherry-picked data that was “most favorable for the study as opposed to the most recent and most complete.”

Only hours earlier, AstraZeneca had issued a news release trumpeting the effectiveness and safety of its vaccine, whose low price has made it the leading vehicle to inoculate people worldwide. The company said that based on its U.S. trial, the vaccine appeared to be 79 percent effective at preventing Covid-19.

But the independent oversight board said in its letter that the vaccine’s efficacy may have been between 69 percent and 74 percent. The letter reprimanded AstraZeneca for an overly rosy description of the trial data.

The letter prompted the National Institute of Allergy and Infectious Diseases to issue a sharply worded statement shortly after midnight on Tuesday, making public the panel’s concerns.

The public airing of a conflict between a pharmaceutical company and a board overseeing a clinical trial is highly unusual. It is almost certain to trigger extra scrutiny of the vaccine by the Food and Drug Administration and other regulators if AstraZeneca seeks emergency authorization of its vaccine in the United States in the coming weeks, as expected. ...