On Mar. 30, 2021, the National Institute of Allergy and Infectious Diseases (NIAID) announced that researchers had analyzed blood cell samples from 30 people who had contracted and recovered from COVID-19 prior to the emergence of virus variants. They found that one key player in the immune response to SARS-CoV-2 – the CD8+ T cell – remained active against the virus.

Although details about the exact levels and composition of antibody and T-cell responses needed to achieve immunity to SARS-CoV-2 are still unknown, scientists assume that strong and broad responses from both antibodies and T cells are required to mount an effective immune response. CD8+ T cells limit infection by recognizing parts of the virus protein presented on the surface of infected cells and killing those cells.

In their study of recovered COVID-19 patients, the researchers determined that SARS-CoV-2-specific CD8+ T-cell responses remained largely intact and could recognize virtually all mutations in the variants studied. While larger studies are needed, the researchers note that their findings suggest that the T cell response in convalescent individuals, and most likely in vaccinees, are largely not affected by the mutations found in these three variants, and should offer protection against emerging variants.