Abstract
The effectiveness of vaccines against COVID-19 on the individual level is well established. However, few studies have examined vaccine effectiveness against transmission. We used a chain binomial model to estimate the effectiveness of vaccination with BNT162b2 [Pfizer-BioNTech messenger RNA (mRNA)-based vaccine] against household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Israel before and after emergence of the B.1.617.2 (Delta) variant. Vaccination reduced susceptibility to infection by 89.4% [95% confidence interval (CI): 88.7 to 90.0%], whereas vaccine effectiveness against infectiousness given infection was 23.0% (95% CI: -11.3 to 46.7%) during days 10 to 90 after the second dose, before 1 June 2021. Total vaccine effectiveness was 91.8% (95% CI: 88.1 to 94.3%). However, vaccine effectiveness is reduced over time as a result of the combined effect of waning of immunity and emergence of the Delta variant.
【초록키워드】 COVID-19, SARS-CoV-2, Vaccine, coronavirus, vaccination, Immunity, susceptibility, variant, Infection, Delta, B.1.617.2, Transmission, delta variant, BNT162b2, Effectiveness, household transmission, confidence interval, Messenger RNA, acute respiratory syndrome, second dose, individual level, examined, reduced, Total, 【제목키워드】 BNT162b2, household contact, transmission of SARS-CoV-2, reduce,