The expressions of antiviral IFN-related genes, including signal transducer and activator of transcription (STAT)2, DEAD box protein 58 (DDX58 or RIG-I), interferon induced with helicase C domain 1 (IFIH1), eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2), IFN regulatory factor (IRF)3, IRF1, and tyrosine kinase 2 (TYK2), were significantly higher in chorion compared to amnion in COVID-19-affected pregnancies (Fig. 2I). Here, TYK2 is linked to COVID-19.