Safety and Efficacy of the BNT162b2 mRNA Covid 19 Vaccine
Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) infection and the resulting coronavirus disease 2019 (Covid 19) have afflicted tens of millions of people in a worldwide pandemic. Safe and effective vaccines are needed urgently. Methods In an ongoing multinational, placebo controlled, observer blinded, pivotal efficacy trial, we randomly assigned persons 16 years of age or older in a 1:1 ratio to receive two doses, 21 days apart, of either placebo or the BNT162b2 vaccine candidate (30 mg per dose) BNT162b2 is a lipid nanoparticle formulated, nucleoside modified RNA vaccine that encodes a prefusion stabilized, membrane anchored SARS CoV 2 full length spike protein. The primary end points were efficacy of the vaccine against laboratory confirmed Covid 19 and safety. Results A total of 43,548 participants underwent randomization, of whom 43,448 received injections: 21,720 with BNT162b2 and 21,728 with placebo. There were 8 cases of Covid 19 with onset at least 7 days after the second dose among participants assigned to receive BNT162b2 and 162 cases among those assigned to placebo; BNT162b2 was 95% effective in preventing Covid 19 (95% credible interval, 90.3 to 97.6) Similar vaccine efficacy (generally 90 to 100% was observed across subgroups defined by age, sex, race, ethnicity, baseline body mass index, and the presence of coexisting conditions. Among 10 cases of severe Covid 19 with onset after the first dose, 9 occurred in placebo recipients and 1 in a BNT162b2 recipient. The safety profile of BNT162b2 was characterized by 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 the vaccine and placebo groups. Conclusions A two dose regimen of BNT162b2 conferred 95% protection against Covid 19 in persons 16 years of age or older. Safety over a median of 2 months was similar to that of other viral vaccines. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.
The New England journal of medicine