Considering that antibody levels against the MERS-CoV S1 antigen, which includes the receptor-binding domain, have remained relatively high in our MERS cohort even during the pandemic (Fig. 1) and exhibit a strong correlation with neutralizing activity against MERS-CoV (Figs. 2J and 4N), the contribution of antibodies specific to the S1 antigen may be more substantial than those targeting MERS-CoV CE#4, which are induced by COVID-19 vaccination and/or SARS-CoV-2 infection. The gene discussed is PSMD1; the disease is COVID-19.