It was quite striking that the 15 individuals recovered from COVID-19 infection who developed mild infection had relatively high Ab reactivity against some parental unmodified peptides from alleles like HLA-DRβ1*0701 (42814, 42800), HLA-DRβ1*0301 (42826) and HLA-DRβ1*0102 (42812) which were not immunogenic in this monkey trial, due to the absence of Aotus alleles Aona DRβ3802 and 4501N. This evidence concerns the gene HLA-DRB1 and infection.