TYK2 and COVID-19: As reported recently, critically ill COVID‐19 patients show genetic polymorphisms in one IFN receptor gene (IFNRA2) and in a gene locus near the Janus kinase (JAK) TYK2, which is key for IFN, interleukin (IL)‐12 and IL‐23 signaling, and T helper (Th) 1/Th17 cell‐mediated antiviral immune responses.