Evaluation of Cellular Responses to ChAdOx1-nCoV-19 and BNT162b2 Vaccinations

While numerous studies have evaluated humoral responses to severe acute respiratory syn-drome coronavirus 2 (SARS-CoV-2) vaccines, data on the cellular responses to these vac-cines remain sparse. We evaluated T cell responses to ChAdOx1-nCoV-19 and BNT162b2 vaccinations using an interferon gamma (IFN-gamma) release assay (IGRA). ChAdOx1-nCoV-19-and BNT162b2-vaccinated participants initially showed stronger T cell responses than unvaccinated controls. The T cell response decreased over time and increased substan-tially after the administration of a BNT162b2 booster dose. Changes in the T cell response were less significant than those in the anti-receptor-binding domain IgG antibody titer. The study results can serve as baseline data for T cell responses after SARS-CoV-2 vaccination and suggest that the IGRA can be useful in monitoring immunogenicity.

Automated summary

T cell responses to ChAdOx1-nCoV-19 and BNT162b2 vaccinations were evaluated using an interferon gamma (IFN-gamma) release assay (IGRA). Initially, ChAdOx1-nCoV-19 and BNT162b2 vaccinated individuals showed stronger T cell responses compared to unvaccinated controls. The T cell response decreased over time but significantly increased after the administration of a BNT162b2 booster dose. Changes in the T cell response were less significant than changes in the anti-receptor-binding domain IgG antibody titer. The study provides baseline data for T cell responses after SARS-CoV-2 vaccination and suggests the usefulness of IGRA in monitoring immunogenicity.