Prognosis
AstraZeneca Pares Covid Vaccine Efficacy Data After U.S. Criticism
- Experts raised concern that earlier rate of 79% was outdated
- Data kerfuffle may delay U.S. approval, adding to vaccine woes
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AstraZeneca Plc reported a slightly lower efficacy rate for its Covid-19 vaccine after the results of an American clinical trial were criticized as outdated, raising further questions over the embattled shot and potentially delaying its approval in the U.S.
The vaccine was 76% effective at protecting volunteers against the coronavirus, the U.K. drugmaker said in a statement on Thursday. That compares with an earlier estimate of 79%, which was based on data gathered through Feb. 17.