Indeed, we found that the polymorphisms in GSTP1, GSTM3, GSTO1 and GSTO2 genes were associated with significant odds of COVID-19 development, while the combined GSTP1 and GSTM3 genotype even exhibited cumulative risk regarding both COVID-19 occurrence and COVID-19 severity [26,28]. This evidence concerns the gene GSTM3 and COVID-19.