Remarkably, the number of NSP12-specific CD4+ T-cell responses was only slightly lower in the samples of individuals without a history of SARS-CoV-2 or pre-pandemic samples compared to COVID-19 patients, indicating an extremely high degree of cross-reactivity of CCC- and SARS-CoV-2 NSP12-specific T-cell responses. This evidence concerns the gene CD4 and COVID-19.