New Study Reveals COVID-19’s Impact on Taste, Independent of Smell, in Over 10,000 Patients
Smell loss has long been recognized as a prominent symptom of COVID-19, leading to extensive research on the functioning of taste and smell. A global study conducted by the Global Consortium for Chemosensory Research (GCCR) and the Monell Chemical Senses Center has now shed light on the impact of COVID-19 on taste, independent of smell, in a diverse group of over 10,000 individuals. Published in Chemical Senses, their findings challenge previous assumptions and provide valuable insights into the effects of the virus.
Although the effect of COVID-19 on the sense of smell is widely acknowledged, its impact on taste perception has received less attention. To address this knowledge gap, the research team set out to empower people worldwide by enabling them to monitor their sense of smell and taste using common household items. The findings from this study represent a unique opportunity to document the influence of early COVID-19 variants on human taste perception, an area that has been understudied and misunderstood.
Led by Ha Nguyen, PhD, the study’s co-first author and a Postdoctoral Fellow at the Monell Chemical Senses Center, alongside other researchers from GCCR, the team analyzed data from a web-based self-assessment survey and an at-home test. Participants were asked to rate the intensity of smell and taste using culturally relevant items found in their homes. The survey also collected demographic and health information, including self-reported positivity to a COVID-19 PCR test.
Among the 10,918 participants who completed the GCCR Smell-and-Taste Check, 3,356 were COVID-positive, 602 were COVID-negative, 1,267 were awaiting test results, and the remaining 5,693 reported no respiratory illness and were not tested for COVID. The results showed that COVID-positive patients experienced a 21% reduction in taste intensity, a 47% reduction in smell intensity, and a 17% reduction in oral irritant intensity compared to those reporting no symptoms.
What makes these findings particularly significant is the ability to separate taste from smell. By using stimuli like salt and sugar, which have no olfactory component, the researchers demonstrated that the intensity of pure taste stimuli was reduced in people with COVID-19, regardless of their smell perception. This evidence strongly supports the hypothesis that COVID-19 affects taste perception independently of smell, as observed in a large and diverse sample.
The study also highlighted the success of online, home-based chemosensory testing, which proved to be an effective model during the pandemic. However, the researchers acknowledged that self-reporting of COVID diagnosis may exclude a significant number of people experiencing smell or taste loss.
Based on their findings, the research team advocates for routine smell and taste testing to benefit all patients with chemosensory effects from COVID-19 and other causes. By expanding our understanding of how the COVID virus and other pathogens impact our senses, we can improve overall health and well-being, develop interventions, and provide valuable insights for diagnosing and treating related conditions.
The Monell Chemical Senses Center, an independent nonprofit research institute based in Philadelphia, Pennsylvania, focuses on advancing scientific knowledge in the realms of taste, smell, and related senses. Their research aims to enhance nutritional health, address smell and taste loss, and digitize chemosensory data, ultimately improving the lives of individuals around the world.
This groundbreaking study not only deepens our understanding of COVID-19 but also highlights the crucial importance of taste perception independent of smell. As the world continues to combat the ongoing pandemic, these findings offer valuable insights that will help researchers develop interventions and improve the overall health and well-being of affected individuals.
