Data from murine models of ARCT-021, another candidate sa-mRNA COVID-19 vaccine encoding the S glycoprotein of the original Wuhan-Hu-1 strain, support this theory, with higher proportions of interferon-γ producing CD8+ and CD4+ T cells across all tested doses of the sa-mRNA vaccine compared with conventional mRNA controls [25]. The gene discussed is CD8A; the disease is COVID-19.