A Clinical Observational Study of SARS-CoV-2 Specific CD8 T-Cell Responses to COVID-19 Vaccines in Humans

Study Description: This study is to identify SARS-CoV-2 S protein specific CD8 T cells in the blood of COVID-19 vaccinated participants. Pfizer and Moderna made vaccines will be used in this study. As both vaccines are mRNA-based encoding S protein of SARS-CoV-2 and require two doses, the CD8 T cell response is expected to be comparable. We will also measure general health factors using blood samples. By analyzing the frequency, differentiation, and expansion of these SARS-CoV-2 S protein specific CD8 T cells, we hope to shed light into the CD8 T cell response to COVID-19 vaccine and its change with age. Objectives: To determine the proportion of individuals who develop and maintain SARS-CoV-2 S protein specific CD8 T cells after vaccination as a proxy for cellular immunity to future SARS CoV-2 exposure, to determine if there are differences in CD8 T cell response to COVID-19 vaccines between young and older healthy adults, and the longevity of CD8 T cell response over a five year follow up. Endpoints: Primary Endpoint: Presence or absence of various SARS-CoV-2 S protein specific CD8 T cells in COVID-19 vaccine participants and their quantitative changes during and after the course of vaccination, and over a five year time. Secondary Endpoint: Determining the effect of age (either prespecify age \>65 vs \<65 or explore as a continuous variable) and sex on presence of SARS-CoV-2 S protein specific CD8 T cells Exploratory Endpoints: 1. Correlations between CD8 T cell responses in vitro and circulating SARS-CoV-2 specific antibodies 2. Plasma inflammatory cytokines and other biomarkers