To assess memory CD4 T cell responses following SARS-CoV-2 infection, we screened 27 ADAPT subjects from the first wave (May-October, 2020; Supplementary Table 1) at 3 months post-infection using recombinant SARS-CoV-2 RBD protein, and using influenza lysate as a control antigen. Here, CD4 is linked to infection.