Study Supports Link Between Loss of Smell, Taste and COVID-19 Infection

April 13, 2020

New research has identified an association between sensory loss and novel coronavirus 2019 (COVID-19) infection.

New research has identified an association between sensory loss and novel coronavirus 2019 (COVID-19) infection, indicating that loss of smell and taste may be considered early symptoms of the virus, according to a study published in the International Forum of Allergy & Rhinology.1  

Although sensory loss has been anecdotally linked to COVID-19 infection, there have been no clinical data to support this association. These are the first empirical findings reported that strongly provide evidence of sensory loss as a COVID-19 symptom, which may help further facilitate screening and early isolation of cases.

Other known symptoms of COVID-19 include fever, fatigue, cough, and difficulty breathing.

The study, which was led by researchers from UC San Diego Health, included 1480 patients with flu-like symptoms and concerns regarding potential COVID-19 infection who underwent testing from March 3 through March 29, 2020.  

Of the 58% of patients who tested positive for COVID-19, smell and taste loss were reported in 68% and 71% of patients, respectively, compared with 16% and 17% of patients who tested negative (p<0.001), according to the study.

Overall, the results demonstrated that smell and taste impairment were independently and strongly associated with COVID-19 positivity (anosmia: adjusted odds ratio [aOR] 10.9, 95% CI: 5.08-23.5; ageusia: aOR 10.2 95% CI 4.74-22.1), whereas sore throat was associated with COVID-19 negativity (aOR 0.23, 95% CI: 0.11-0.50).

Related: Study Suggests Digestive Symptoms May Be Associated with COVID-19

“Based on our study, if you have smell and taste loss, you are more than 10 times more likely to have COVID-19 infection than other causes of infection,” Carol Yan, MD, an otolaryngologist and head and neck surgeon at UC San Diego Health, said in a statement.2 “The most common first sign of a COVID-19 infection remains fever, but fatigue and loss of smell and taste follow as other very common initial symptoms. We know COVID-19 is an extremely contagious virus. This study supports the need to be aware of smell and taste loss as early signs of COVID-19.”

Additionally, the researchers noted that, of those who reported loss of smell and taste, the loss was typically profound, not mild. The rate of recovery of smell and taste was high and usually occurred within 2 to 4 weeks of infection. Of the patients who reported COVID-19 associated loss of smell, 74% reported resolution of anosmia with clinical resolution of illness.

“It is our hope that with these findings other institutions will follow suit and not only list smell and taste loss as a symptom of COVID-19, but use it as a screening measure for the virus across the world,” Dr Yan said in the statement.2

References:

1. Yan CH, Faraji F, Prajapati DP, et al. Association of chemosensory dysfunction and Covid-19 in patients presenting with influenza-like symptoms. International Forum of Allergy & Rhinology. April 12, 2020. Doi: https://doi.org/10.1002/alr.22579

2. Loss of Smell and Taste Validated as COVID-19 Symptoms in Patients with High Recovery Rate. News Release. UC San Diego; April 13, 2020. https://ucsdnews.ucsd.edu/pressrelease/loss-of-smell-and-taste-validated-as-covid-19-symptoms-in-patients-with-high-recovery-rate. Accessed April 13, 2020.