Alliance for Pandemic Preparedness

January 25, 2021

The Proportion of SARS-CoV-2 Infections That Are Asymptomatic



Keywords (Tags):

At least one third of SARS-CoV-2 infections were characterized as asymptomatic in a systematic review of cross-sectional and longitudinal observational studies and reports of mass screening for SARS-CoV-2. Most studies (43/61) used PCR testing of nasopharyngeal swabs to detect current infection, and 18 studies used antibody testing to detect current or prior infection. In 14 studies with longitudinal data, nearly 75% of individuals who were asymptomatic at the time of testing remained asymptomatic. 

Oran and Topol. (Jan 22, 2021). The Proportion of SARS-CoV-2 Infections That Are Asymptomatic. Annals of Internal Medicine.