KIR2DS4 and COVID-19: Remarkably, considerable literature is supportive of the latter interpretation, as several reports from different populations with high prevalence of the functional KIR2DS4*001 gene (58, 59) delineate a risk association of HLA-A*11:01, HLA-C*05:01, HLA-C*04:01, and HLA-C*16:01 to the severe or fatal COVID-19 (16, 17, 19, 21, 22, 34, 60–64), and all of those alleles are recognized by the functional KIR2DS4.