Figure 1. Outline of the study. Patients with a confirmed subjective diagnosis of COVID-19 related olfactory dysfunction were recruited two weeks after the onset of symptoms. Sniffing test (identification part of the TDI) was performed and the SARS-CoV-2 viral load was measured in the nasal wash two weeks after the first day of symptom reported. Antibody levels to SARS-CoV-2 and to endemic coronaviruses were measured in nasal wash and serum. Based on their sniffing test, anosmic and hyposmic patients have been regrouped in one group called “anosmic”.