The findings of a study published in the International Forum of Allergy & Rhinology suggests that clinicians should include sensory impairment as standard screening measure after the first empirical findings were reported that strongly associate sensory loss with COVID-19.

The study was conducted by researchers at the University of California San Diego Health who surveyed 1480 patients with flu-like symptoms and concerns regarding potential COVID-19 infection who underwent testing at from March 3 through March 29. The study included responses from 59 COVID-19-positive patients and 203 COVID-19-negative patients.

“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. “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.”

Yan said the study demonstrated the high prevalence and unique presentation of certain 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 usually within two to four weeks of infection.

“Our study not only showed that the high incidence of smell and taste is specific to COVID-19 infection, but we fortunately also found that for the majority of people sensory recovery was generally rapid,” said Yan. “Among the Covid-19 patients with smell loss, more than 70% had reported improvement of smell at the time of survey and of those who hadn’t reported improvement, many had only been diagnosed recently.”

Sensory return typically matched the timing of disease recovery. Interestingly, the researchers found that persons who reported experiencing a sore throat more often tested negative for COVID-19.

In an effort to decrease 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.

Respondents in Yan’s study were most often persons with milder forms of COVID-19 infection who did not require hospitalisation or intubation. The findings, she said, underline the importance of identifying early or subtle symptoms of COVID-19 infection in people who may be at 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.

Source: https://ucsdnews.ucsd.edu/pressrelease/loss-of-smell-and-taste-validated-as-covid-19-symptoms-in-patients-with-high-recovery-rate

Reference: Yan CH, et al. Association of chemosensory dysfunction and Covid‐19 in patients presenting with influenza‐like symptoms. International Forum of Allergy & Rhinology. Published 12 April 2020