AUTHOR=Hurme Antti , Jalkanen Pinja , Heroum Jemna , Liedes Oona , Vara Saimi , Melin Merit , Teräsjärvi Johanna , He Qiushui , Pöysti Sakari , Hänninen Arno , Oksi Jarmo , Vuorinen Tytti , Kantele Anu , Tähtinen Paula A. , Ivaska Lauri , Kakkola Laura , Lempainen Johanna , Julkunen Ilkka TITLE=Long-Lasting T Cell Responses in BNT162b2 COVID-19 mRNA Vaccinees and COVID-19 Convalescent Patients JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.869990 DOI=10.3389/fimmu.2022.869990 ISSN=1664-3224 ABSTRACT=

The emergence of novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made it more difficult to prevent the virus from spreading despite available vaccines. Reports of breakthrough infections and decreased capacity of antibodies to neutralize variants raise the question whether current vaccines can still protect against COVID-19 disease. We studied the dynamics and persistence of T cell responses using activation induced marker (AIM) assay and Th1 type cytokine production in peripheral blood mononuclear cells obtained from BNT162b2 COVID-19 mRNA vaccinated health care workers and COVID-19 patients. We demonstrate that equally high T cell responses following vaccination and infection persist at least for 6 months against Alpha, Beta, Gamma, and Delta variants despite the decline in antibody levels.