Some recent research has shown that loss of smell and taste have been linked to COVID-19 infections. A new study published on April 12, 2020, in the journal International Forum of Allergy & Rhinology, researchers at UC San Diego Health have discovered the first experimental findings that strongly associate sensory loss with COVID-19, the respiratory disease caused by the new coronavirus.
“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.”
Carol Yan and her colleagues surveyed 1,480 patients that presented flu-like symptoms and concerns regarding a potential infection with the novel coronavirus. They have begun testing at UC San Diego Health on March 3 and finished on March 29, 2020. Their results have shown a total of 102 patients who tested positive for the virus and the last 1,378 tested negative. Their study involved responses from 59 COVID-19-positive patients and 203 COVID-19-negative patients.
Carol Yan also explained that the study proved the high frequency and unique presentation of certain sensory impairments regarding positive patients with COVID-19. The patients who reported a loss of smell and taste have experienced a profound loss, not mild. However, some encouraging data has shown that 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 percent 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.”
Additionally, the loss of smell and taste usually begun to fade, typically matching the timing of disease recovery. Moreover, the researchers found that patients who reported experiencing a sore throat more often tested negative for COVID-19. In an effort to put a stop on the increase in COVID-19 cases, UC San Diego Health now includes symptoms such as loss of smell and taste as a screening requirement for visitors and staff, as well as a red flag for testing patients who may be positive for the virus.
Other COVID-19 symptoms include fever, fatigue, cough and difficulty breathing. However, it’s important to mention that the respondents in Yan’s study were most often patients with milder forms of COVID-19 infection who did not require hospitalization 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.
Study co-authors include Farhoud Faraji, Divya P. Prajapti, Christine E. Boone and Adam S. DeConde, all at UC San Diego. This research was funded, in part, by the National Institutes of Health (grant UL1TR001442).