NVX-CoV2373 vaccination induces functional SARS-CoV-2–specific CD4(+) and CD8(+) T cell responses

NVX-CoV2373 is an adjuvanted recombinant full-length SARS-CoV-2 spike trimer protein vaccine demonstrated to be protective against COVID-19 in efficacy trials. Here we demonstrate that vaccinated individuals made CD4(+) T cell responses after 1 and 2 doses of NVX-CoV2373, and a subset of individuals made CD8(+) T cell responses. Characterization of the vaccine-elicited CD8(+) T cells demonstrated IFN-γ production. Characterization of the vaccine-elicited CD4(+) T cells revealed both circulating T follicular helper (cTfh) cells and Th1 cells (IFN-γ(+), TNF-α(+), and IL-2(+)) were detectable within 7 days of the primary immunization. Spike-specific CD4(+) T cells were correlated with the magnitude of the later SARS-CoV-2–neutralizing antibody titers, indicating that robust generation of CD4(+) T cells, capable of supporting humoral immune responses, may be a key characteristic of NVX-CoV2373 that utilizes Matrix-M adjuvant.