Abstract
The BNT162b2 vaccine showed high efficacy against COVID-19 in a phase III randomized clinical trial. A vaccine effectiveness evaluation in a real-world setting is needed. To assess the short-term effectiveness of the first dose of the BNT162b2-vaccine against SARS-CoV-2 infection 13 to 24 days after immunization in a real-world setting. This comparative effectiveness study used data from a 2.6 million-member state-mandated health care system in Israel. Participants included all individuals aged 16 years and older who received 1 dose of the BNT162b2 vaccine between December 19, 2020, and January 15, 2021. Data were analyzed in March 2021. Receipt of 1 dose of the BNT162b2 vaccine. Information was collected regarding medical history and positive SARS-CoV-2 polymerase chain reaction test and COVID-19 symptoms from 1 day after first vaccine to January 17, 2021. Daily and cumulative infection rates in days 13 to 24 were compared with days 1 to 12 after the first dose using Kaplan-Meier survival analysis and generalized linear models. Data for 503 875 individuals (mean [SD] age, 59.7 [14.7] years; 263 228 [52.4%] women) were analyzed, of whom 351 897 had follow-up data for days 13 to 24. The cumulative incidence of SARS-CoV-2 infection was 2484 individuals (0.57%) during days 1 through 12 and 614 individuals (0.27%) in days 13 through 24. The weighted mean (SE) daily incidence of SARS-CoV-2 infection in days 1 through 12 was 43.41 (12.07) infections per 100 000 population and 21.08 (6.16) infections per 100 000 population in days 13 through 24, a relative risk reduction (RRR) of 51.4% (95% CI, 16.3%-71.8%). The decrease in incidence was evident from day 18 after the first dose. Similar RRRs were calculated in individuals aged 60 years or older (44.5%; 95% CI, 4.1%-67.9%), those younger than 60 years (50.2%; 95% CI, 14.1%-71.2%), women (50.0%; 95% CI, 13.5%-71.0%), and men (52.1%; 95% CI, 17.3%-72.2%). Findings were similar in subpopulations (eg, ultraorthodox Jewish: RRR, 53.5% [95% CI, 19.2%-73.2%]) and patients with various comorbidities (eg, cardiovascular diseases: RRR, 47.2% [95% CI, 7.8%-69.8%]). Vaccine effectiveness against symptomatic COVID-19 was 54.4% (95% CI, 21.4%-73.6%). In this comparative effectiveness study of a single dose of the BNT162b2 vaccine, results were comparable to that of the phase III randomized clinical trial.
Highlights
The recently authorized BNT162b2 COVID-19 vaccine (BioNTech, Pfizer) has demonstrated 95% efficacy in preventing COVID-19 with the 2-dose regimen in a phase III placebo-controlled randomized clinical trial (RCT),[1] with the second dose given 21 days after the first vaccine dose
The weighted mean (SE) daily incidence of SARS-CoV-2 infection in days 1 through 12 was 43.41 (12.07) infections per 100 000 population and 21.08 (6.16) infections per 100 000 population in days 13 through 24, a relative risk reduction (RRR) of 51.4%
Similar RRRs were calculated in individuals aged 60 years or older (44.5%; 95% CI, 4.1%-67.9%), those younger than 60 years (50.2%; 95% CI, 14.1%-71.2%), women (50.0%; 95% CI, 13.5%-71.0%), and men (52.1%; 95% CI, 17.3%-72.2%)
Summary
The recently authorized BNT162b2 COVID-19 vaccine (BioNTech, Pfizer) has demonstrated 95% efficacy in preventing COVID-19 with the 2-dose regimen in a phase III placebo-controlled randomized clinical trial (RCT),[1] with the second dose given 21 days after the first vaccine dose. The BNT162b2 RCT1 showed vaccine efficacy of 52% (95% CI, 29.5%- 68.4%) between the first dose and the second dose, with reduction in risk compared with the placebo starting as soon as 12 days after the first dose This is comparable with the minimal acceptable level of efficacy of 50% in preventing COVID-19 as indicated by the World Health Organization[5] and by the US Food and Drug Administration[6] as one of the essential criteria to confer emergency use approval to COVID-19 candidate vaccines. Assessment of the vaccine effectiveness in real life outside of clinical trial settings is warranted, especially given the complex and unusual storage and handling requirements of BNT162b2 vaccine
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