Auto-Abs neutralizing IFN-α and/or IFN-ω have also recently been shown to underlie ∼40% of cases of West Nile virus encephalitis, the most severe form of West Nile disease (Gervais et al., 2023), and ∼10% of cases of severe tick-borne encephalitis (TBE) (Gervais et al., 2024). This evidence concerns the gene IFNA2 and tick-borne encephalitis.