CD4 and COVID-19: Thus, most COVID-19 vaccine efforts focus on the elicitation of neutralizing antibodies (Amanat and Krammer, 2020; Corey et al., 2020; Thanh Le et al., 2020), with additional interest in elicitation of CD4+ or CD8+ T cells (Corbett et al., 2020; Folegatti et al., 2020; Jackson et al., 2020; Mercado et al., 2020; Sahin et al., 2020).