Some patients who have been infected with still-inscrutable COVID-19 have in the last few months said their sense of smell and taste disappeared. But these reports have been merely anecdotal. 

Now, Israeli researchers who conducted a huge, crowdsourced survey of COVID-19 patients from over 40 countries supplies the greatest evidence so far of the link between COVID-19 and the loss of smell, taste and chemesthesis – the ability to perceive cooling, tingling and burning sensations from stimulants such as menthol and chili peppers. 

The team, led by scientists from the Hebrew University of Jerusalem, say these findings will eventually help distinguish COVID-19 patients from those with common viral infections, such as the common cold or the flu, and help prioritize the limited supply of COVID-19 tests. 

Prof. Masha Niv, vice dean at the Hebrew University’s Faculty of Agriculture, Food and Environment, is a leading member of The Global Consortium for Chemosensory Research (GCCR) that launched this survey on April 7, 2020.  They mined the database on April 18 for initial findings and have posted their results on medRxiv.

The results were based on 4,039 COVID-19-positive participants from around the world. The GCCR found that smell, taste and chemesthesis are significantly reduced during the illness and that a stuffed nose, for example, is not the cause of these sense losses, suggesting that these symptoms may be an important way to distinguish COVID-19 infection from other viral infections. 

“Our findings show that COVID-19 broadly impacts chemosensory function and is not limited to smell loss. Disruption in these functions should be considered a possible indicator of COVID-19,” explained Niv. 

The ongoing survey asks participants who have been diagnosed with COVID-19 to quantify their smell, taste and chemesthetic senses both before and during the illness, and to report any nasal blockages. This project is distinct from previous studies on chemosensory and COVID-19 in that it leverages a multinational, “open-science” approach.   The survey is available in 27 languages, including English, French, Spanish, German, Italian, Japanese, Arabic, Norwegian, Spanish, Swedish and Turkish.  So far, over 30,000 responses have been crowdsourced through traditional print, television, radio and social media. 

“What’s needed to fight a global pandemic is a global approach,” declared Niv. “That’s what GCCR does best. We’ve harnessed scientists, clinicians and patients from around the world to give us a better understanding of the disease’s impact on various populations and to provide us with significant clues towards better diagnosis and treatment of the COVID-19 disease.”