Effectiveness of BNT162b2 Vaccine against Omicron Variant Infection among Children 5–11 Years of Age, Israel

Abstract

We assessed effectiveness of the BNT162b2 vaccine against infection with the B.1.1.529 (Omicron) variant (mostly BA.1 subvariant), among children 5–11 years of age in Israel. Using a matched case–control design, we matched SARS-CoV-2–positive children (cases) and SARS-CoV-2–negative children (controls) by age, sex, population group, socioeconomic status, and epidemiologic week. Vaccine effectiveness estimates after the second vaccine dose were 58.1% for days 8–14, 53.9% for days 15–21, 46.7% for days 22–28, 44.8% for days 29–35, and 39.5% for days 36–42. Sensitivity analyses by age group and period demonstrated similar results. Vaccine effectiveness against Omicron infection among children 5–11 years of age was lower than vaccine efficacy and vaccine effectiveness against non-Omicron variants, and effectiveness declined early and rapidly.

Keywords

• COVID-19
• 2019 novel coronavirus disease
• coronavirus disease
• severe acute respiratory syndrome coronavirus 2
• SARS-CoV-2
• viruses