CD4 and COVID-19: Independent groups have shown that CD4+ and CD8+ T-cell responses in convalescent COVID-19 subjects and SARS-CoV-2 mRNA vaccinees are not substantially affected by mutations found in the SARS-CoV-2 variants (3–5) and that the impaired neutralization capacity of sera against the alpha VOC after two BNT162b2 doses seems to be negligible (6–9).