Alliance for Pandemic Preparedness

October 19, 2020

Herd Immunity and Implications for SARS-CoV-2 Control



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An infection-based herd immunity approach, in which low-risk groups become infected while higher-risk groups are sheltered, has been proposed as a strategy for response to the SARS-CoV-2 pandemic. Omer et al. describe methods for estimating the herd immunity threshold and estimate a SARS-CoV-2 herd immunity threshold of 50-67%. Because most, if not all of the population lacks immunity to the novel SARS-CoV-2 virus, they estimate that around 198 million people in the US would have to be infected to reach a herd immunity threshold of 60%, which would result in several hundred thousand additional deaths using an estimated infection fatality rate of 0.5%. The authors highlight the importance of efficient and widespread vaccination campaigns to reach the herd immunity threshold. 

Omer et al. (Oct 19, 2020). Herd Immunity and Implications for SARS-CoV-2 Control. JAMA.