CD4 and COVID-19: Except for the ORF1ab5019–5033 and ORF7a98–112 epitopes, we found that a strong positive linear correlation existed between the high magnitude of IFN-γ-producing CD4+ T-cell responses specific to 14 CD4+ T-cell epitopes and the “natural protection” observed in unvaccinated asymptomatic COVID-19 patients (Figures 1A, C).