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Real-World Effectiveness of BNT162b2 mRNA COVID-19 Vaccine
Quick Takes
- This case-control study reports the real-world effectiveness of the BNT162b2 mRNA COVID-19 vaccine using data from the nationwide vaccination campaign in Israel.
- The effectiveness of BNT162b2 after the second dose was 92% for documented infection, 94% for symptomatic COVID-19, 87% for hospitalization, and 92% for severe disease, and was consistent across age groups.
- The effectiveness for preventing death from COVID-19 after the first dose (before the second dose) was 72%.
Study Questions:
What is the real-world effectiveness of the BNT162b2 mRNA coronavirus disease 2019 (COVID-19) vaccine?
Methods:
The authors leveraged data from integrated health care organizations in Israel where a nationwide vaccination campaign is underway and emulated the BNT162b2 vaccine clinical trial. All persons (ages ≥16 years, without previously documented positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who were newly vaccinated during the period from December 20, 2020, to February 1, 2021, were matched to unvaccinated controls in a 1:1 ratio according to variables associated with probability of both vaccination and infection or severity of COVID-19. Population groups with disproportionate probability of exposure or outcome were excluded (e.g., recent exposure to the health care system, nursing home residents, health care workers). Study outcomes included documented infection with SARS-CoV-2, symptomatic COVID-19, COVID-19–related hospitalization, severe illness, and death. Analysis was stratified according to timeline: days 14-20 after first dose, and ≥7 days after second dose.
Results:
Of 1,503,216 CHS members who were vaccinated, 1,163,534 were eligible for the study and 596,618 were matched to unvaccinated controls. Given the smaller pool of unvaccinated matches for older vaccine recipients, matched controls were younger and had a lower prevalence of chronic conditions. Estimated vaccine effectiveness for the study outcomes at days 14-20 after the first dose and at ≥7 days after the second dose was as follows: for documented infection, 46% (95% confidence interval [CI], 40-51) and 92% (95% CI, 88-95); for symptomatic COVID-19, 57% (95% CI, 50-63) and 94% (95% CI, 87-98); for hospitalization, 74% (95% CI, 56-86) and 87% (95% CI, 55-100); and for severe disease, 62% (95% CI, 39-80) and 92% (95% CI, 75-100), respectively. Estimated effectiveness in preventing death from COVID-19 was 72% (95% CI, 19-100) for days 14-20 after the first dose. The effectiveness was consistent across age groups, with potentially slightly lower effectiveness in persons with multiple coexisting conditions.
Conclusions:
Real-world data suggest that the BNT162b2 mRNA vaccine is effective for a wide range of COVID-19–related outcomes, a finding consistent with that of the randomized trial.
Perspective:
Data from close to 600,000 persons in the mass vaccination campaign in Israel confirm the high effectiveness of the BNT162b2 mRNA vaccine in preventing both serious and mild COVID-19–related outcomes, notably after the second dose. Protection after a single dose averaged 50% for asymptomatic and symptomatic infection, and 72% for COVID-19–related death. These findings support the benefit of a two-dose vaccination regimen. To conform with the clinical trial and limit confounding, the study excluded high-risk populations such as nursing home residents and health care workers. A close examination of the effectiveness in these populations is warranted as measures to mitigate the pandemic are slowly being lifted.
Clinical Topics: COVID-19 Hub, Prevention
Keywords: Coronavirus, COVID-19, Critical Illness, Mass Vaccination, Primary Prevention, RNA, Messenger, severe acute respiratory syndrome coronavirus 2, Vaccination
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