CD4 and infection: The individual frequencies of IFN-γ and IL2 responses in asymptomatic and symptomatic participants to the S, N+M, and CD4+CD8 pools at T0, T7, T14 and TLT are shown in S1 and S2 Figs. The frequencies of IFN-γ and IL2 responses to S and N+M pools significantly (p = <0.001) rose at 7 days after infection and persisted unchanged at TLT (>28 days).