Scientists confirm smell and taste loss as early signs of COVID-19

San Diego, Apr 15: Several people lost their sense of smell or taste weeks ago globally and are still waiting for it to come back and now, researchers have identified an association between sensory loss and novel coronavirus 2019 (COVID-19) infection, indicating that loss of smell and taste may be considered as early symptoms of the deadly disease.

Interestingly, the study also found that persons who reported experiencing a sore throat more often tested negative for COVID-19.

The team from University of California-San Diego found high prevalence and unique presentation of certain sensory impairments in patients positive with COVID-19.

Of those who reported a loss of smell and taste, the loss was typically profound, not mild.

"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," explained study researcher Carol Yan from UC San Diego.

"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 added.

For the findings, published in the journal International Forum of Allergy and Rhinology, the research team surveyed 1,480 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 1,378 tested negatives. The study included responses from 59 COVID-19-positive patients and 203 COVID-19-negative patients.

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 per cent had reported improvement of smell at the time of the survey and of those who hadn't reported improvement, many had only been diagnosed recently," she added.

Sensory return typically matched the timing of disease recovery.

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.

"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.