Effectiveness of BNT162b2 Vaccine Booster Against SARS-CoV-2 Infection and Breakthrough Complications, Israel

Aharona Glatman-Freedman; Michal Bromberg; Yael Hershkovitz; Hanna Sefty; Zalman Kaufman; Rita Dichtiar; Lital Keinan-Boker


Emerging Infectious Diseases. 2022;28(5):948-956. 

In This Article

Abstract and Introduction


We estimated vaccine effectiveness (VE) of the BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) booster dose against SARS-CoV-2 infection and reduction of complications (hospitalization, severe disease, and death) among breakthrough cases in persons in Israel ≥16 years of age for ≤20 weeks. VE estimates reached 96.8% (95% CI 96.0%–97.5%) for persons 16–59 years of age and 93.1% (95% CI 91.8%–94.2%) for persons ≥60 years of age on week 3. VE estimates remained at these levels for 8 weeks in the 16–59 age group and 11 weeks in those ≥60. A slow decline followed, becoming more pronounced in the last 2–3 weeks of evaluation. Estimates in the last week of evaluation were 77.6% (95% CI 68.4%–84.2%) and 61.3% (52.5%–68.4%) for persons 16–59 years and ≥60 years, respectively. The more pronounced VE decline coincided with rapid increase in Omicron variant activity. Rate reduction of breakthrough complications remained moderate to high throughout the evaluation.


The mass severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BNT162b2 (Pfizer-BioNTech, https://www.pfizer.com) vaccination campaign in Israel was associated with a decline in the number of SARS-CoV-2 infections, hospitalizations, and deaths, reaching a nadir by mid-May 2021.[1] However, beginning the third week of June 2021, a new rise in the number of SARS-CoV-2 cases was observed, including cases among fully vaccinated persons.[1,2] Waning humoral immune response after the second vaccine dose was then found to be associated with increased incidence of SARS-CoV-2–related infections, hospitalizations, and deaths caused primarily by the B.1.617.2 (Delta) variant.[3] In response to the increasing illness and deaths, the Israel Ministry of Health (MOH) recommended a third (booster) BNT162b2 vaccine dose for persons for whom at least 5 months had passed after receiving the second vaccine dose.[4] The elderly and other high-risk groups were prioritized at first,[4] and other age groups were added rapidly thereafter.[5] We estimated the booster dose vaccine effectiveness (VE) against SARS-CoV-2 infection and the rate reduction of complications in breakthrough coronavirus disease (COVID-19) cases after the BNT162b2 booster dose in persons ≥16 years of age, by age group, for up to 20 weeks after receipt of the booster dose.