CD4 and COVID-19: Th1 and Th17 are often characterized by CXCR3 (Ward et al., 1998) and CCR6 (Singh et al., 2008), respectively, and CXCR3+ and CCR6+ SARS-CoV-2-specific CD4+ T cells were both detected during acute COVID-19 (Juno et al., 2020; Moderbacher et al., 2020).