'Incredible milestone for science.' Pfizer and BioNTech update their promising COVID-19 vaccine result

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.