VDR and COVID-19: To further investigate genetic effects between COVID-19 phenotype and vitamin D, all SNPs (total of 578) located in the GC gene (chromosome 4, 72607410–72671237; 168 SNPs), DHCR7/NADSYN1 (chromosome 11, 71164249–71212862; 230 SNPs), VDR (chromosome 12, 48235320–48298777; 154 SNPs), and CYP2R1 (chromosome 11, 14898986–14913777; 9 SNPs) were extracted.