TYK2 and COVID-19: Subsequent studies such as the ones from the GenOMICC (Genetics Of Mortality In Critical Care) initiative and the COVID-19 HGI have discovered multiple additional variants and genes associated with susceptibility to or severity of infection, including loci involved in inflammation or innate immunity, such as the OAS1/OAS2/OAS3 gene cluster encoding activators of antiviral restriction enzymes [10–12], the interferon receptor gene IFNAR2 [10–13], the inflammasome regulator DPP9 [10–13], and the tyrosine kinase 2 (TYK2) [10, 11] important for antiviral responses (Fig. 1).