Genetic deficiencies in components of the type I IFN signaling pathway, including IFNAR1 and IFNAR2, along with downstream kinases JAK1 and TYK2, are associated with development of severe COVID-19 [52, 53] while expression of certain alleles of IFN-induced dsRNA sensor OAS1 correlate with reduced disease severity [54, 55]. Here, TYK2 is linked to COVID-19.