The proportion of individuals with hypoxemic COVID-19 due to neutralizing both IFN-α2 and IFN-ω at the high dose (10 ng/mL) is even higher in the breakthrough cohort reported here (7 of 42, 16%) than in the previously described unvaccinated cohort (175 of 3,136, 7.1%) (P = 0.015) (22). Here, IFNA2 is linked to COVID-19.