Therapeutic effects of olfactory training and systemic vitamin A in patients with COVID-19-related olfactory dysfunction: a double-blinded randomized controlled clinical trial

The new corona virus infection, has a wide range of clinical manifestations. Fever and cough are the most common symptoms. The olfactory function may be also affected with COVID-19. In this randomized clinical trial, we wanted to evaluate the therapeutic effect of olfactory training with and without oral vitamin A for COVID-19-related olfactory dysfunction.