Inclusion Criteria:  A random sample of at least 100 adults with sudden hyposmia/anosmia and/or hypoageusia/ageusia during COVID-19 pandemics which persist till the onset of the study. Persisting symptoms were defined by the presence at day 30 or day 60 of anosmia/ageusia. Patients who experienced persistent olfactory and/or smell manifestations after recovery from their initial acute COVID-19 illness.  Exclusion Criteria:  Prior neurologic, medical or psychiatric disease. Other known infection at onset Nasal congestion Nasal polyps Surgery or head trauma or radiation for head and neck cancers as may result in injury to the nerves that control smell Exposure to toxic chemicals (such as pesticides and solvents) Cocaine or other drug abuse