About Serology Surveillance

Reported coronavirus disease, COVID-19, cases likely represent only a fraction of all SARS-CoV-2, the virus that causes COVID-19 infections. CDC is using information from COVID-19 seroprevalence surveys to learn more about past SARS-CoV-2 infections, often not accounted for in reported cases. Seroprevalence surveys are investigations that involve the use of serology test (also known as antibody tests)to better understand how many SARS-CoV-2 infections have occurred at different points in time, in different locations, and in different populations in the United States.