IRCT20210205050247N1 IRCT 2021-02-13 Bagheiat-allah University of Medical Sciences The effect of olfactory training and vitamin A in the olfactory loss of patients with covid-19. A comparative study of the effect of olfactory training and vitamin A in the olfactory loss of patients with covid-19. 2021-02-18 anticipated 90 Complete https://irct.ir/trial/54178 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment, Randomization description: Patients will be divided into three groups of 30 in a simple random method according to the table of random numbers, Blinding description: In a double-blind study, both participants and researchers or outcome assessors are unaware of the allocation of study groups. 1 olfactory loss. Intervention 1: Intervention group: This group will be treated with respiratory physiotherapy or olfactory rehabilitation for 12 weeks. Intervention 2: Intervention group: The second group will be treated with vitamin A tablets (10,000 units per day) along with the olfactory rehabilitation method for 12 weeks. Intervention 3: Control group: The third group of patients will not receive any treatment intervention and these patients will be followed up for 12 weeks. No - There is not a plan to make this available Justification or reason for not sharing IPD is There is no more information