Similar doses of mRNA-1273 (25 μg) to the BNT162b2 dose (30 μg) generated comparable Spike-specific memory CD4 T-cell frequencies to natural infection and about half as strong as those seen with high-dose vaccination (100 μg) indicating that differences between cellular and humoral immunity after two mRNA vaccines most likely result from the different doses of the vaccine (48). The gene discussed is CD4; the disease is infection.