AstraZeneca has revised down by three percentage points the effectiveness of its Covid vaccine after American authorities raised concerns that results reported from its US trial were outdated.
The company now says its vaccine is 76% rather than 79% effective at preventing any kind of symptomatic Covid. It remains 100% effective against severe Covid, it added.
The move came after an independent panel of experts appointed to supervise the trial expressed concern that AstraZeneca had failed to include updated data in its initially released figure.
The US National Institutes of Health then issued a highly unusual statement asking AstraZeneca to work with the panel and issue a new press release. "We look forward to filing our regulatory