CD4 and infection: We confirmed that the first vaccination rapidly provoked antigen-specific AIM+ circulating follicular helper T (cTFH) cells (CD3+CD4+CD45RA+CXCR5+ T cells) in peripheral blood40, while the CXCR3+ cTFH subset, which is preferentially induced in the TH1 cell condition and associated with efficient antibody responses in the context of infections and vaccinations32,41,42, was the major subset of cTFH cells induced by mRNA vaccination (Fig. 2c,d).