Alliance for Pandemic Preparedness

March 30, 2021

SARS-CoV-2 Infection Risk among Unvaccinated Is Negatively Associated with Community-Level Vaccination Rates

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  • [Pre-print, not peer-reviewed] Increases in the proportion of individuals aged 16-50 years receiving the first dose of the Pfizer-BioNTech vaccine were followed by declines in the SARS-CoV-2 positivity rate among a bystander unvaccinated cohort of people under 16 years old in 223 geographically defined communities in Israel. The proportion of vaccinated individuals and SARS-CoV-2 positivity rate of the unvaccinated cohort was measured at three different intervals between January and March 2021, with a 35-day delay in between to allow for the immunization effects of the vaccine to take effect. A strong negative correlation was observed when comparing the change in proportions of individuals vaccinated to the change in positivity rate of the unvaccinated cohort. While communities included in the study had a low pre-vaccination community-level positivity rate (3.6%), the authors note that decline in the SARS-CoV-2 positivity rate among the bystander unvaccinated cohort could be affected by acquired immunity from prior infection, as well as individual behavior and public policy guidelines.

Milman et al. (Mar 29, 2021). SARS-CoV-2 Infection Risk among Unvaccinated Is Negatively Associated with Community-Level Vaccination Rates. Pre-print downloaded Mar 30 from https://doi.org/10.1101/2021.03.26.21254394