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 μg 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 .)

Prior COVID-19 significantly reduces the risk of subsequent infection, but reinfections are seen after eight months

“…Nonetheless, even with the limited number of reinfections, prior infection still confers a protective effect of 94% over the time of the study. This is equivalent to or better than the protection reported in recent vaccine studies 9,10 . The requirement to isolate (sometimes repeatedly) may adversely affect education, employment and mental health.…”

“…Further studies and longer surveillance are needed to confirm the duration of protection following previous SARS-CoV-2 infection, as well as the likelihood of subclinical infection and the impact of the evolution of new variants of the virus. In addition, as various national COVID-19 vaccination programmes get underway, it is important to remember that patients with prior SARS-CoV-2 antibodies were excluded from some of the vaccine studies 9,10 , and the efficacy of the vaccines on patients with prior immunity is unknown, and should perhaps be studied further.…”

Filling the Gap Until Full Vaccine Deployment in the War on Coronavirus Disease-19

“…Following accelerated development, Phase 3 testing of some vaccine candidates is currently under way [16]. On the basis of data from the ongoing large-scale clinical trial [17], one of these vaccine candidates (BNT162b2) has been found to be effective and safe enough for the release of an emergency-use authorization (EUA) or equivalents in the United Kingdom (UK), Canada, and the USA at the beginning of December 2020. BNT162b2 and other vaccine candidates may soon be cleared for a similar emergency use in other countries, but there are limited data about long-term safety, efficacy in high-risk demographic groups, the magnitude of the protection, and the duration of the vaccine immunity [18,19].…”

Simulated identification of silent COVID-19 infections among children and estimated future infection rates with vaccination

“…[5][6][7] Global efforts to contain this deadly disease have led to the development of several vaccine candidates in different stages of clinical trials. 8 The efficacy results of two vaccines (Pfizer-BioNTech, Moderna) 9,10 have exceeded the World Health Organization preferred populationbased efficacy of 70% for a COVID-19 vaccine. 11 The US Food and Drug Administration (FDA) has authorized emergency use of these vaccines in the US population.…”