Government

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.”

Federal health officials said early Tuesday that results from a U.S. trial of AstraZeneca’s Covid-19 vaccine may have relied on “outdated information” that “may have provided an incomplete view of the efficacy data,” casting doubt on an announcement on Monday that had been seen as good news for the British-Swedish company as well as the global vaccination drive.