COVID-19 vaccine trial complete, Pfizer and BioNTech update their promising result

Jon Cohen

Not to be outdone by a rival with a similar product, Pfizer and BioNTech today provided an update on the previously announced success of their COVID-19 vaccine. The U.S. pharma giant and its German biotech partner now report 95 percent efficacy for their vaccine candidate, drawing on the final analysis of a 43,000-person study. And don’t worry about the elderly not responding to the vaccine; the efficacy only drops to 94 percent in people over 65 years of age, the companies said in a press release.

As opposed to the vague initial report last week that their vaccine had greater than 90 percent efficacy, Pfizer and BioNTech are providing more specific data now that the study has reached enough COVID-19 cases to end the study. In all, the trial had 162 confirmed cases of symptomatic COVID-19 in the placebo group versus 8 among those who received the scheduled two doses of the vaccine. The efficacy, which was measured 7 days after the second dose of the vaccine, was the same in different race 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 had 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 percent 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 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 “within days” it will submit a request to the U.S. Food and Drug Administration for emergency use authorization (EUA) of the companies’ vaccine. If recent history repeats itself, Moderna will follow suit about one week later. The 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- Science


  • Science’s COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation.