The strongest association with severe or critical pneumonia was that for children with auto-Abs neutralizing both IFN-α2 and IFN-ω at a concentration of 10 ng/ml (OR [95% CI] = 122.8 [12.8–16,364.8], P = 6 × 10−6; OR, odds ratio; CI, confidence interval). The gene discussed is IFNA2; the disease is pneumonia.