Intranasal administration of IFN-based therapeutics, either prophylactically or shortly after infection, has been shown to limit SARS-CoV-2 replication in nasal passages, but differences between respiratory and olfactory IFN responses and viral replication have not been directly measured [60, 61], making it difficult to interpret whether there may be tissue-specific effects of IFN in the URT. The gene discussed is IFNA1; the disease is infection.