There are commercially available antibody tests that can distinguish between antibodies from natural infection and from the common vaccines. https://www.cdc.go

There are commercially available antibody tests that can distinguish between antibodies from natural infection and from the common vaccines. https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antibody-tests-guidelines.html https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/anti... >The first vaccines distributed in the United States induce antibodies to S protein. Thus, presence of antibodies to N protein indicates previous natural infection regardless of vaccination status, while presence of antibodies to S protein indicates either previous natural infection or vaccination.