Saussez S, Sharma S, Thiriad A, et al. - In the present study, the researchers sought to assess potential predictive factors of smell recovery in a clinical series of 288 patients presenting olfactory dysfunction (OD) related to the COVID19. Potential correlations between patients' epidemiological, clinical, and immunological characteristics and the persistence of OD at 60 days are being investigated. COVID-19 positive patients with OD were recruited prospectively from three European hospitals. Baseline clinical and olfactory evaluations were conducted within the first 2 weeks after OD onset and repeated at 30 and 60 days. In total, 288 COVID-19 patients with OD were involved in the study. No significant correlation was found between gender, age, viral load on the nasopharyngeal swab or COVID-19 severity and poor olfactory outcome. At 60 days, no clinical markers predicted the evolution of OD. Patients who had a poor olfactory outcome at 60 days had lower saliva and nasal antibodies, implying that local immune responses play a role in the persistence of COVID-19-related OD.