Allele T ACE2 rs2074192 (OR = 3.45; p = 0.009), allele A IFNAR2 rs2236757 (OR = 2.62; p = 0.039), allele A OAS1 rs10774671 (OR = 4.60; p = 0.003) and allele C CD40 rs4813003 (OR = 4.75; p = 0.037) are associated with severe COVID-19 that could advance to MIS-C. This evidence concerns the gene CD40 and COVID-19.