Long-standing gustatory and olfactory dysfunction in COVID-19 patients: a prospective study

Purpose: Our study aimed to describe recovery of gustatory dysfunction (GD) and olfactory dysfunction (OD) in COVID-19 patients, and to analyze variables associated with early or late recovery. Methods: Telephone surveys were administered during an 18-month follow-up after COVID-19 diagnosis. One hundred and thirty-two included patients rated olfactory and gustatory function at each follow-up. Results: One hundred and twenty-nine patients reported GD, of whom 91 (70.5%) reported severe GD, and 99 patients reported OD, of whom 84 (84.9%) reported severe OD. Seventy-two/129 (55.8%) and 52/99 (52.5%) patients reported an improvement in GD and in OD during the first 7 days from the onset, respectively. At 3-month follow-up, 110/120 patients (85.3%) recovered from GD, while 80/99 patients (80.8%) recovered from OD. At 18-month follow-up, a total of 120/129 patients (93.0%) recovered from GD and 86/99 patients (86.9%) recovered from OD; while 10 patients (7.0%) still reported GD and 13 patients (13.1%) still reported OD. Severe GD/OD at presentation were associated with late complete recovery of taste/smell (p = 0.019 and p = 0.034, respectively). Improvement over the first 7 days from onset was significantly associated with faster recovery (p < 0.001). Conclusions: More than 80% of patients reported complete recovery of olfactory/gustatory function in the first 3 months after symptom onset. At 18-month follow-up, patients reporting complete recovery of gustatory and olfactory function were 93% and 87%, respectively. Severity of chemosensory dysfunction at the onset was negatively correlated to recovery, and improvement of taste and/or smell function within the first 7 days from symptom onset was significantly associated with early resolution.