As opposed to the vague initial report last week that their vaccine had greater than 90% efficacy, Pfizer and BioNTech are providing more specific data now that the study has reached enough COVID-19 cases to end. In all, the trial had 162 confirmed cases of symptomatic COVID-19 in the placebo group versus eight among those who received the two scheduled doses of the vaccine. The efficacy, which was measured 7 days after the second dose of the vaccine, was the same in different races and ethnicities, the companies say—although subgroup analyses always have more uncertainty. Nine of the 10 people who had severe cases of COVID-19 during the trial received the placebo, which indicates that even if the vaccine fails to prevent symptomatic disease, it still offers powerful protection from serious harm. No serious side effects surfaced, the companies report, although 3.7% of the vaccinated reported fatigue after the injections.
The results are nearly identical to preliminary findings reported by Moderna on 16 November from its ongoing efficacy trial. Both its vaccine and the Pfizer/BioNTech candidate contain messenger RNA (mRNA) that codes for the surface protein of SARS-CoV-2, the virus that causes COVID-19. The strategy is novel—no medicines made from mRNA have been approved for widespread human use so far.
The Pfizer/BioNTech collaboration says it will submit “within days” a request to the U.S. Food and Drug Administration for emergency use authorization (EUA) of its vaccine. If recent history repeats itself, Moderna will follow suit about 1 week later. FDA has said it will convene its independent vaccine advisory committee to review any COVID-19 EUA requests, and the first meeting could occur as early as 9 December, an agency official tells ScienceInsider.
“This is a remarkable and very reassuring situation that we find ourselves in,” says Trudie Lang, who directs the Global Health Network at the University of Oxford. “To go from identifying a new virus to having several vaccines at the point of applying for regulatory approval is an incredible milestone for science.”