Revealing the mystery of persistent smell loss in Long COVID patients

Jung Woo Park^1,2,✉, Xiaoyan Wang^1,2, Ren-He Xu^1,2

1. Center of Reproduction, Development & Aging, and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
2. Ministry of Education Frontiers Science Center for Precision Oncology, University of Macau, Taipa, Macau, China.

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Citation:
Park JW, Wang X, Xu RH. Revealing the mystery of persistent smell loss in Long COVID patients. Int J Biol Sci 2022; 18(12):4795-4808. doi:10.7150/ijbs.73485. Available from https://www.ijbs.com/v18p4795.htm

Abstract

COVID-19 is hopefully approaching its end in many countries as herd immunity develops and weaker strains of SARS-CoV-2 dominate. However, a new concern occurs over the long-term effects of COVID-19, collectively called “Long COVID”, as some symptoms of the nervous system last even after patients recover from COVID-19. This review focuses on studies of anosmia, i.e., impairment of smell, which is the most common sensory defect during the disease course and is caused by olfactory dysfunctions. It remains mysterious how the olfactory functions are affected since the virus can't invade olfactory receptor neurons. We describe several leading hypotheses about the mystery in hope to provide insights into the pathophysiology and treatment strategies for anosmia.

Keywords: COVID-19, long COVID, olfactory dysfunction