HLA-C and COVID-19: In contrast, the HLA-B*38 and HLA-C*06 alleles, both analyzed in the same 4 articles (5 studies) [39, 55, 56, 62], were associated with risk for the most severe form of COVID-19 (OR = 1.64, 95% CI 1.03–2.60 and OR = 1.31, 95% CI 1.00–1.72, respectively; S4 Table and Fig 3C and 3D).