CD4 and COVID-19: SARS-CoV-2 antigen-specific adaptive immune responses (ADIM) have been inferred from surrogate markers in large studies (Laing et al., 2020; Lucas et al., 2020; Mathew et al., 2020), and some antigen-specific T cell (Meckiff et al., 2020; Weiskopf et al., 2020) or neutralizing antibody data (Robbiani et al., 2020; Rogers et al., 2020; Wajnberg et al., 2020) are available, but combined assessments of antigen-specific CD4+ T cells, CD8+ T cells, and neutralizing antibodies in acute COVID-19 are still lacking (except 3 subjects in Zhou et al., 2020b).