CD44 and infection: Moreover, in context to memory CD4+ TEM (CD44+CD62L −) cell subset, relatively higher frequencies were observed for immunized mice subjected to infection with SARS-CoV-2 variants USA-WA1/2020 (Vaccinated = 15.4% vs. Mock = 8.3%, p = 0.0001), Alpha (B.1.1.7) (Vaccinated = 12.3% vs. Mock = 8.7%, p < 0.0001), and Beta (B.1.351) (Vaccinated = 6.8% vs. Mock = 6%, p < 0.0004) (Figure 4D).