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Chemosensory Dysfunctions Induced by COVID-19 Can Persist up to 7 Months: A Study of Over 700 Healthcare Workers

  • Bussière, Nicholas1
  • Mei, Jie1
  • Lévesque-Boissonneault, Cindy1
  • Blais, Mathieu2, 3
  • Carazo, Sara4
  • Gros-Louis, Francois2, 3
  • De Serres, Gaston4
  • Dupré, Nicolas5, 6
  • Frasnelli, Johannes1
  • 1 Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC , (Canada)
  • 2 Axe Médecine régénératrice, CHU de Québec-Université Laval, Québec City, QC , (Canada)
  • 3 Faculty of Medicine, Department of Surgery, Université Laval, Québec City, QC , (Canada)
  • 4 Institut National de Santé Publique du Québec, Québec City, QC , (Canada)
  • 5 Faculty of Medicine, Department of Medicine, Université Laval, Québec City, QC , (Canada)
  • 6 Axe Neurosciences, CHU de Québec–Université Laval, Québec City, QC , (Canada)
Published Article
Chemical Senses
Oxford University Press
Publication Date
Aug 23, 2021
DOI: 10.1093/chemse/bjab038
PMID: 34423831
PMCID: PMC8499810
PubMed Central
  • AcademicSubjects/SCI01180


Several studies have revealed either self-reported chemosensory alterations in large groups or objective quantified chemosensory impairments in smaller populations of patients diagnosed with COVID-19. However, due to the great variability in published results regarding COVID-19-induced chemosensory impairments and their follow-up, prognosis for chemosensory functions in patients with such complaints remains unclear. Our objective is to describe the various chemosensory alterations associated with COVID-19 and their prevalence and evolution after infection. A cross-sectional study of 704 healthcare workers with a RT–PCR-confirmed SARS-CoV-2 infection between 2020 February 28 and 2020 June 14 was conducted 3–7 months after onset of symptoms. Data were collected with an online questionnaire. Outcomes included differences in reported chemosensory self-assessment of olfactory, gustatory, and trigeminal functions across time points and Chemosensory Perception Test scores from an easy-to-use at-home self-administered chemosensory test. Among the 704 participants, 593 (84.2%) were women, the mean (SD) age was 42 (12) years, and the questionnaire was answered on average 4.8 (0.8) months after COVID-19. During COVID-19, a decrease in olfactory, gustatory, and trigeminal sensitivities was reported by 81.3%, 81.5%, and 48.0%, respectively. Three to 7 months later, reduced sensitivity was still reported by 52.0%, 41.9%, and 23.3%, respectively. Chemosensory Perception Test scores indicate that 19.5% of participants had objective olfactory impairment. These data suggest a significant proportion of COVID-19 cases have persistent chemosensory impairments at 3–7 months after their infection, but the majority of those who had completely lost their olfactory, gustatory, and trigeminal sensitivities have improved.

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