Results: In 97 COVID-19-positive patients (52 mild, 24 moderate, and 21 severe) and 100 healthy volunteers, the study revealed protective associations with inhibitory alleles (KIR2DL1, KIR2DL3, KIR2DL4, KIR3DL1, KIR3DL2, and pseudo-alleles like KIR3DP1⁣∗003). This evidence concerns the gene KIR3DL1 and COVID-19.