TMPRSS2 and COVID-19: <h4>Aim</h4>To assess the association of single nucleotide polymorphisms (SNPs) in the ACE2 and TMPRSS2 genes with COVID-19 severity and key biomarkers.<h4>Methods</h4>The study involved 750 COVID-19 patients from Bosnia and Herzegovina, divided into three groups: mild, moderate, and severe cases.