PROS1 and infection: The detection values (AU/mL) of N and S proteins for SARS-CoV-2 in the HD-COVID-19 groups were above the threshold (5 AU/mL), and those of S1 protein in the HDs with vaccine group were high, indicating that the serum utilized in this experiment showed the state of recovery after natural infection with SARS-CoV-2 and after injection of the mRNA vaccine incorporating S protein (Supplementary Table 2).