COVID-19:Recovery from Chemosensory Dysfunction. A Multicentre study on Smell and Taste

Objective With the COVID-19 pandemic chemosensory dysfunction are among the most prevalent symptoms. Most reports are subjective evaluations, which has been suggested to be unreliable. The objective is to test chemosensory dysfunction and recovery based on extensive psychophysical tests in COVID-19 during the course of the disease. Methods 111 patients from four centres participated in the study. All tested positive for SARS-COV-2 with RT-PCR. They were tested within three days of diagnosis and 28 to 169?days after infection. Testing included extensive olfactory testing with the Sniffin? Sticks test for threshold, discrimination and identification abilities, and with the Taste Sprays and Taste Strips for gustatory function for quasi-threshold and taste identification abilities. Results There was a significant difference in olfactory function during and after infection. During infection 21% were anosmic, 49% hyposmic and 30% normosmic. After infection only 1% were anosmic, 26% hyposmic and 73% normosmic. For gustatory function there was a difference for all taste qualities, but significantly in sour, bitter and total score. 26% had gustatory dysfunction during infection and 6.5% had gustatory dysfunction after infection. Combining all tests 22% had combined olfactory and gustatory dysfunction during infection. After infection no patients had combined dysfunction. Conclusion Chemosensory dysfunction is very common in COVID-19, either as isolated smell or taste dysfunction or a combined dysfunction. Most people regain their chemosensory function within the first 28?days, but a quarter of the patients show persisting dysfunction, which should be referred to specialist smell and taste clinics for rehabilitation of chemosensory function.