Published on Fri Jul 16 2021

Vaccination with BNT162b2 reduces transmission of SARS-CoV-2 to household contacts in Israel

Prunas, O., Warren, J. L., Crawford, F. W., Gazit, S., Patalon, T., Weinberger, D. M., Pitzer, V. E.

Few studies have directly examined the effect of COVID-19 vaccines on transmission. We quantified the effectiveness of vaccination with BNT162b2 against household transmission of SARS-CoV-2 in Israel. Vaccine effectiveness against susceptibility to infection was 80-88%.

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Abstract

The individual - level effectiveness of vaccines against clinical disease caused by SARS-CoV-2 is well-established. However, few studies have directly examined the effect of COVID-19 vaccines on transmission. We quantified the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech mRNA-based vaccine) against household transmission of SARS-CoV-2 in Israel. We fit two time-to-event models - a mechanistic transmission model and a regression model - to estimate vaccine effectiveness against susceptibility to infection and infectiousness given infection in household settings. Vaccine effectiveness against susceptibility to infection was 80-88%. For breakthrough infections among vaccinated individuals, the vaccine effectiveness against infectiousness was 41-79%. The overall vaccine effectiveness against transmission was 88.5%. Vaccination provides substantial protection against susceptibility to infection and slightly lower protection against infectiousness given infection, thereby reducing transmission of SARS-CoV-2 to household contacts.