Consistent with previous studies showing impaired interferon response to infection associated with COVID-19 [3, 7–9] and functional analysis suggesting the virus is vulnerable to IFNγ [12], we show that a key IFNγ precursor, interleukin-18, is associated with a lower risk of any COVID-19 and possibly of very severe COVID-19. The gene discussed is IL18; the disease is COVID-19.