Publication date: May 11, 2026
Olfactory dysfunction is a hallmark feature of COVID-19, yet the potential for recovery with long-standing COVID-19-related smell loss (CRSL) remains uncertain, particularly when treatment is initiated years later. This study evaluated olfactory outcomes in patients with CRSL compared with non-COVID-19-related smell loss (non-CRSL), with emphasis on delayed treatment initiation. This retrospective cohort study included 104 patients evaluated at a tertiary clinic between January 2023 and February 2025, comprising 47 patients with CRSL and 57 with non-CRSL. All patients completed serial Sniffin’ Sticks testing (threshold, discrimination, and identification [TDI]) at ≥2 visits. Minimal clinically important difference (MCID) was defined as a ≥5. 5-point increase in TDI score. All patients received olfactory training combined with twice-daily steroid nasal irrigation. Subgroup analyses examined delayed treatment initiation (>2 years), treatment adherence, and COVID-19 vaccination status. Baseline TDI scores were higher in the CRSL group than in the non-CRSL group (19. 6 +/- 6. 3 vs. 16. 8 +/- 6. 8; p 2 years after onset. Prospective studies are needed to clarify causal relationships given known spontaneous recovery in post-viral olfactory dysfunction.
| Concepts | Keywords |
|---|---|
| Discrimination | COVID‐19 |
| February | long‐term outcomes |
| Vaccination | olfactory dysfunction |
| Viral | post‐viral anosmia |
| smell loss |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 |
| disease | MESH | smell loss |
| disease | MESH | included |