Olfactory dysfunction in patients after recovering from COVID-19

Acta Otolaryngol. 2020 Dec;140(12):1032-1035. doi: 10.1080/00016489.2020.1811999. Epub 2020 Aug 27.


Background: Smell and taste disorders occur in COVID-19 with a high prevalence, but little is known about the duration of the symptoms. In particular, studies using validated olfactory tests are very rare to date.

Aims/objectives: The aim of this study was to determine the olfactory function of COVID-19 recoveries by a detailed olfactory test.

Methods: 91 patients with PCR-confirmed, past COVID-19 disease were included. Olfactory history was taken using a questionnaire. Olfactory function was evaluated with the sniffin' sticks test, tasting function with taste sprays.

Results: 80 patients had experienced sudden olfactory loss during the course of disease and at the time of testing, 33 patients subjectively still had an impaired olfactory sense. Around 8 weeks had passed since the onset of symptoms. 45.1% of the tested individuals were still hyposmic according to the olfactory test while 53.8% showed an olfactory performance within the normal range. Patients' self-assessment correlated poorly with the measured olfactory performance.

Conclusions and significance: Half of the patients with an olfactory loss as a symptom of COVID-19 still have olfactory impairments after two months, although not all of these patients subjectively notice a restriction. Long-term measurements must confirm whether all affected patients will make full recovery.

Keywords: Covid-19; Sars-CoV-2; Sniffin’ sticks; smell disorders; smell test.

MeSH terms

  • Adult
  • COVID-19 / complications*
  • COVID-19 / epidemiology
  • COVID-19 / physiopathology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Olfaction Disorders / diagnosis
  • Olfaction Disorders / etiology*
  • Pandemics
  • SARS-CoV-2*
  • Sensory Thresholds / physiology*
  • Smell / physiology*