The GWAS conducted by the Genetics Of Mortality In Critical Care (GenOMICC) assessed critically ill COVID-19 patients from UK intensive care units (ICUs) and identified 2′-5′-Oligoadenylate Synthetase (OAS) gene cluster on chromosome 12 (OAS1, OAS2 and OAS3), a single nucleotide variant (SNV) each in Tyrosine Kinase 2 (TYK2) and Dipeptidyl Peptidase 9 (DPP9) genes on chromosome 19 and a single nucleotide polymorphism (SNP) in the interferon receptor gene Interferon Alpha and Beta receptor subunit 2 (IFNAR2) on chromosome 21. Here, DPP9 is linked to COVID-19.