Global survey supports link between COVID-19 and loss of smell and taste

News release provided by Penn State University and modified to include University of Florida-specific information.

Jeb Justice., and Steven Munger
Jeb M. Justice, M.D. and Steven D. Munger, Ph.D.

UNIVERSITY PARK, Pa. — A new massive crowdsourced survey of COVID-19 patients from around the world provides the greatest evidence to date of a link between COVID-19 and the loss of smell, taste and chemesthesis — or sensitivity to chemicals such as those in chili peppers. The findings may have implications for prioritizing the limited supply of COVID-19 tests.

Based on entries from 4,039 participants representing more than 40 countries, the initial findings reveal that smell, taste and chemesthesis are significantly reduced in patients diagnosed with COVID-19. Importantly, nasal blockage does not appear to be associated with these losses, suggesting that they may be an important way to distinguish COVID-19 infection from other viral infections, such as cold or flu.

“Our findings show that COVID-19 broadly impacts chemosensory function and that disruption in these functions should be considered a possible indicator of COVID-19,” said John Hayes, associate professor of food science, Penn State. “The results may give doctors more confidence in recommending telehealth patients for in-person testing while physical distancing remains in place.”

Researchers in the Global Consortium for Chemosensory Research (GCCR) — including Steven D. Munger, Ph.D., director of UF’s Center for Smell and Taste and member of the GCCR leadership team, and Jeb M. Justice, M.D., co-director of the UF Health Smell Disorders Program —  launched the survey on April 7 and queried the database 11 days later, on April 18, for the purpose of reporting initial results, which posted to MedRxiv on Friday, May 8.

The researchers distributed the questionnaire globally in 10 languages — English, French, German, Italian, Japanese, Kannada, Norwegian, Spanish, Swedish and Turkish — although, as of April 30, it is now deployed in 27 languages. Responses were crowdsourced through traditional print, television and radio media; social media; flyers; professional networks; and word of mouth.

“The size and speed of this global study, which is still ongoing, was only possible because of the immense efforts of an international consortium of chemosensory scientists, clinicians and patient advocates who came together in light of the COVID-19 pandemic,” said Munger.

The survey measures self-reported smell and taste in participants who were diagnosed with either an objective test, such as a swab test, or as the result of clinical observations by a medical professional within the two weeks prior to completing the questionnaire.

Participants were asked to quantify their smell and taste, as well as their chemesthetic function — their ability to smell, taste and perceive cooling, tingling and burning sensations — before and during the illness. They were also asked to quantify any nasal blockages.

“For both diagnosis methods, we observed significant quantitative changes in smell, taste and chemesthesis with COVID-19,” said Hayes. “We can conservatively conclude that a major drop in these chemosensory abilities is a hallmark of COVID-19.”

Hayes noted the project is distinct from prior studies on chemosensory and COVID-19 in that it leverages a massive crowd-sourced, multinational approach and does so within a collaborative open-science framework.

“Our hope is that an inclusive globally deployed assessment, coupled with publicly accessible data shared under contemporary open-science best practices will serve as a foundation for future work,” he said.

Read the paper in MedRxiv.