Olfactory recovery following Omicron variant infection: A psychophysical prospective case-control study with 6 month follow-up

Objective: The aim of this study was to evaluate the recovery of olfactory function at 6 months in individuals infected with the omicron variant, using psychophysical tests. Methods: prospective case-control study including SARS-CoV-2 patients infected in February and March 2022. Patients underwent Sniffin'Sticks test (SST) within 10 days of infection and at least 6 months. The olfactory scores were compared with those of a control group. Results: 102 patients and 120 controls were enrolled in the study. At baseline, 26 patients (25.5%) self-reported smell loss. The median TDI score was 33.6 [IQR 12.5] for the cases and 36.5 [IQR 4.38] for the controls (p<0.001). Based on the TDI scores, 12 controls and 34 patients reported olfactory dysfunction (OD) (p<0.001). Eighty cases underwent re-evaluation at 6 months, the median TDI score was 37.1 [IQR 4.75] without significant differences with the controls. Conclusion: six months after infection, the prevalence of OD in patients did not differ significantly from the control population.