Loss of Smell and Taste

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Examining the loss of taste and smell have never been more visible. When the U.S. Centers for Disease Control announced that the sudden loss of taste and smell was one of the six primary symptoms of COVID-19, Monell researchers moved quickly to launch research to better understand the chemosensory nuances of COVID-19. On other research fronts, the loss of smell (anosmia) is an increasing problem as we age, with adverse consequences on quality of life, social interactions, safety, and dietary habits. While less common, taste loss, such as that from radiation to the oral cavity for cancer, poses an equally important challenge to maintain a sufficient appetite during treatments. Monell is also a leader in using cultured human olfactory and taste cells to model the molecular intricacies of taste and smell loss.

The better you measure the more olfactory deficit you find related to COVID-19, and Monell is involved in several ways to do just that. Participants in the Sense of Smell and COVID-19 study use a set of scratch-and-sniff odor cards based on the NIH Toolbox Odor ID Test, that directly tests one’s ability to smell a set of common odors. Another Monell review of over 100 smell studies found that tests asking participants to directly smell a sample odor reported 70 percent of subjects losing their sense of smell; however, self-report tests showed that only 50 percent of subjects claimed to have an olfactory deficit. And watch this space for more details about the pilot study on our rapid smell test for COVID-19.

The Global Consortium for Chemosensory Research, an international group of researchers coalesced over the course of a weekend in early March after the first reports of Covid-19 related smell and taste loss were reported. Monell was at the center of its formation and remains integral to its continued research. These efforts have brought Monell faculty and staff directly onto the frontline of this pandemic. In one of its first publications, they found that in just over 4,000 participants with confirmed COVID-19, smell, taste, and chemosensory function were significantly reduced compared to their status before infection, suggesting that COVID-19 may disrupt sensory-neural pathways. Their preliminary findings confirmed loss of smell as a diagnostic symptom for COVID-19.

Are cultured human taste cells susceptible to the novel coronavirus, specifically cells that display the surface receptor ACE2 and co-receptor TMPRSS2 that the coronavirus uses to enter cells? Monell and colleagues’ taste cell lines will be used to determine the effect of COVID-19 infection on the cells’ ability to replicate and whether certain sub-types are more prone to being infected by the novel coronavirus.