CD4 and infection: To test the hypothesis that vaccination of COVID-19 convalescent patients (CCPs) would induce a repertoire of spike-specific CD4+ T cells distinct from those circulating after natural infection, we tested for T cell responses at a median of 101 (range: 35–161) days after resolution of COVID symptoms and at a median of 72 days (range: 14–241) after the second dose of either the mRNA-1273 [Moderna] or the BNT 162b2 [Pfizer-BioNTech] vaccines in 10 CCPs.