Several elevated AD marker genes (e.g., FERMT2, HLA-DRB1, GNA15, STAB1, ICA1L, COLGALT1, TNFAIP2, ITGAM, VASP, IDLIA, PVR, TECPR1) were increased in the COVID-19 group. Here, HLA-DRB1 is linked to COVID-19.