SARS-CoV-2 infection displays immense inter-individual clinical variability, ranging from silent infection to lethal disease. The role of human genetics in determining clinical response to the virus remains unclear. Studies of outliers-individuals remaining uninfected despite viral exposure and healthy young patients with lifethreatening disease-present a unique opportunity to reveal human genetic determinants of infection and disease.

The risk of life-threatening COVID-19 pneumonia increases sharply after 65 years of age, but other epidemiological risk factors, genetic or otherwise, are modest. Various rare monogenic inborn errors of type I interferons (IFNs) underlie critical disease, and neutralizing autoantibodies against type I IFNs account for at least 10% of critical cases.

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