Patients with COVID-19 who have been referred or admitted to Qaem, Imam Reza, or Shariati Hospital diagnosed with a protocol defined by the World Health Organization.
People who have not experienced any signs of reduced sense of smell and taste for at least 2 weeks before the onset of the first manifestation of Covid-19.
People who were diagnosed with hyposmia or anosmia.
People with certain underlying conditions (such as Parkinson's, Alzheimer's, severe nutritional disorders, acute rhinitis, acute catarrhal sinusitis, SICA syndrome (especially after radiation), nasal mucosal congestion, for example after rhinoplasty, olfactory nerve damage in trauma, etc., which are exposed to the reduction of the sense of smell independent of the coronavirus, as well as, people who experience other viral and bacterial infections simultaneously with COVID-19
People with a history of asthma and allergies are excluded
Participants who refused to participate in follow-up measurements, provide data, or give consent considered withdrawn.