Safety, efficacy of BNT162b2 mRNA (Pfizer/BioNTech) COVID-19 vaccine

Editor's Note

This study reports the safety and efficacy findings of the phase 2 and phase 3 parts of the clinical trial of the BNT162b2 mRNA (Pfizere/BioNTech) vaccine in preventing COVID-19 in persons 16 years of age or older. These results are the basis for an application for emergency use authorization from the Food and Drug Administration.

A total of 43,448 participants were randomized to receive a two-dose regimen of injections—21,720 with the vaccine and 21,728 with a placebo.

Of 10 cases of severe COVID-19 with onset after the first dose, 9 occurred in placebo recipients and 1 occurred in a vaccine recipient.

There were 8 cases of COVID-19 in vaccine recipients with onset at least 7 days after receiving the second dose and 162 cases of COVID-19 in those who received a second dose of the placebo.

Similar vaccine efficacy was found across subgroups defined by age, gender, race, ethnicity, body-mass index, and presence of coexisting conditions.

The safety profile of the vaccine included short-term, mild-to-moderate pain at the injection site, fatigue, and headache. The incidence of serious adverse events was low and was similar in both groups.

The findings show that a two-dose regimen of the vaccine conferred 95% protection against COVID-19, and safety over a median of 2 months was similar to that of other viral vaccines, the researchers say.