The Food and Drug Administration (FDA) is advising against the use of SARS-CoV-2 antibody tests to evaluate immunity or protection from COVID-19 after vaccination.
According to the FDA safety communication, currently authorized SARS-CoV-2 antibody tests are not validated to evaluate immunity or protection from COVID-19. These tests have also not been evaluated to assess the level of immunity or protection provided by an immune response to COVID-19 vaccination.
In individuals without a history of natural infection, post-vaccination antibody tests results will be negative if the test used does not detect the antibodies induced by the vaccine (ie, COVID-19 mRNA vaccines induce antibodies to the spike protein and not to nucleocapsid proteins). As such, serologic testing should only be ordered by health care providers familiar with the use and limitations of these tests.
Interim recommendations for use of serologic tests can be found on the CDC website.
Antibody testing is not currently recommended to assess immunity after COVID-19 vaccination: FDA safety communication. [press release]. Silver Spring, MD: US Food and Drug Administration; May 19, 2021.