Loss of smell and taste has been anecdotally linked to coronavirus disease 2019 (COVID-19) infections, according to a study published in the journal International Forum of Allergy & Rhinology, which reported the first empirical findings that strongly associate sensory loss 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. 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," said Carol Yan, MD, an otolaryngologist and head and neck surgeon at UC San Diego Health, in a press release. "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."
The research team surveyed 1480 patients with flu-like symptoms and concerns regarding potential COVID-19 infection who underwent testing at UC San Diego Health from March 3 through March 29, 2020. Within that total, 102 patients tested positive for the virus and 1378 tested negative. The study included responses from 59 patients who tested positive for COVID-19 and 203 patients who tested negative.
The study demonstrated the high prevalence and unique presentation of sensory impairments in patients positive with COVID-19. Of those who reported loss of smell and taste, the loss was typically profound not mild. But encouragingly, the rate of recovery of smell and taste was high and occurred within 2 to 4 weeks of infection. Among patients with COVID-19 who experienced smell loss, more than 70% reported improvement in smell detection at the time of survey and of those who hadn’t reported improvement, many had been diagnosed recently.
Sensory return typically matched the timing of disease recovery. The researchers also found that patients who reported experiencing a sore throat more often tested negative for COVID-19.
In an effort to decrease the risk of virus transmission, UC San Diego Health now includes loss of smell and taste as a screening requirement for visitors and staff, as well as a marker for testing patients who may be positive for the virus.
Other known symptoms of COVID-19 include fever, fatigue, cough, and difficulty breathing. Respondents were most often patients with milder form of COVID-19 infection who did not require hospitalization or intubation. The findings underline the importance of identifying early or subtle symptoms of COVID-19 infection in patients who may have risk of transmitting the disease as they recuperate within the community.
"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," Yan said.
- Loss of Smell and Taste Validated as COVID-19 Symptoms in Patients with High Recovery Rate. UC San Diego News Center website. Published 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 16, 2020.