CD4 and COVID-19: The primary objectives of the study are to elucidate the immunogenic responses of AA30CH in COVID-19 prophylaxis by determining the antigen density and identifying the variation in immunological markers and lymphocyte subsets CD3, CD4, CD8, CD24, CD27, CD-38, CD4 IFN-γ, CD4 CD17, CD4 CD25 (activated T lymphocytes), T cells, B cells, dendritic cells (DCs; mature and immature), and NK cells; and to estimate the innate and acquired immune responses by real-time RT-PCR array analysis (see Multimedia Appendix 1).