HLA-DRB1 and infection: The same was for all the allelic combinations, with a stronger significance for those containing the HLA-B*08:01g and/or the HLA-DRB1*03:01g allele (Table 6) In contrast, the allelic frequencies of HLA-B*18:01, HLA-C*07:01 and HLA-DRB1*11:04 were all inversely related to the number of Covid-19 cases and deaths, having the southern regions higher frequencies and lower incidence and mortality associated to the infection.