Genes such as SLC6A20, LZTFL1, IFNAR2, DPP9, CCHCR1, ELF5, ATP11A and THBS3 have been identified as potentially contributing to severe COVID-19 and hospitalization in genome-wide association studies (Severe Covid-19 GWAS Group et al., 2020; Lee et al., 2021; Horowitz et al., 2022; Kousathanas et al., 2022; Pairo-Castineira et al., 2021). Here, DPP9 is linked to COVID-19.