October 2, 2025

Olfactory Dysfunction After SARS-CoV-2 Infection in the RECOVER Adult Cohort
These results come from a prospective cohort study that included adults enrolled in the Researching COVID to Enhance Recovery (RECOVER)–Adult study. All those with and a random sample of those without self-reported change or loss in smell or taste were offered olfactory testing, performed at 83 sites in 35 U.S. states and territories. Participants included 2,956 enrollees with prior infection (1393 with and 1563 without self-reported change or loss) and 569 without prior infection (nine with and 560 without self-reported change or loss in taste) who underwent olfactory testing a mean (SD) of 671.6 (417.8) days after the index date. Among 1,393 infected participants with self-reported change or loss, (79.8%) had hyposmia on the University of Pennsylvania Smell Identification Test, (UPSIT),including 321 (23.0%) with severe microsmia or anosmia. Among 1,563 infected participants without self-reported change or loss, 1,031 (66.0%) had hyposmia, including 128 (8.2%) with severe microsmia or anosmia. In this cohort, self-reported change or loss in smell or taste was an accurate signal of verified hyposmia, but a high rate of hyposmia among those with no reported change or loss was also observed. Formal smell testing may be considered in those with prior SARS-CoV-2 infection to diagnose occult hyposmia and counsel patients about risks.