May 22, 2020
An antibody test looks for the presence of specific proteins made in response to infections. This can be helpful in determining who has already been exposed to the virus, and may be resistant to infection again. Antibodies can be found in the blood of people who are tested after infection and show that people have had an immune response to the infection. It typically takes 1 to 3 weeks after someone becomes infected with SARS-CoV-2 for their body to make antibodies (sometimes longer). The CDC is careful to point out that, while some evidence has shown the presence of SARS-CoV-2 antibodies to provide short-term immunity to subsequent infections (a few months), we don’t yet have a clear determination what level of antibodies would be necessary to provide that protection or how long that immunity would last.