The research published in JAMA Otolaryngology-Head & Neck Surgery estimated that between 700,000 and 1.6 million people in the US who had Covid-19 have lost or had a change in their sense of smell that has lasted for more than 6 months. This is likely an underestimate, the authors from Washington University School of Medicine in St. Louis said.
“These data suggest an emerging public health concern of OD and the urgent need for research that focuses on treating COVID-19 COD,” the study said.
“The long-term disease burden from this, we’re literally going to be dealing with this for decades,” according to John Hayes, director of the Sensory Evaluation Center at Penn State’s College of Agricultural Sciences. Hayes did not work on this study but has done research in the area.
He thinks the estimated number of people in the study with this problem is conservative and the issue could impact many millions more.
“It’s really consequential to appetite and social relations, like people have lost their sense of smell may not be able to detect if they have body odor, and can impact diet too,” Hayes said.
Hayes said his research with Covid-19 patients has shown that they’ve experienced three different kinds of long-term olfactory disturbances.
Some lose or have a diminished sense of smell. Some have a sense of smell that is off, where instead of flowers, for example, someone would smell stinky feet. Others may have what Hayes calls a kind of “phantom limb syndrome” for a sense of smell, where people smell things that aren’t actually there, like a persistent chemical or burning smell.
Dr. Sandeep Robert Datta, a neurobiologist at Harvard Medical School who has been studying why people with Covid-19 lose their sense of smell, said this is an important line of research.
“We’ve never really had a formal estimate made of how many people have been struggling with this,” Datta said. “This is a really unusual event in terms of olfactory dysfunction and an unprecedented consequence of a pandemic that’s never really been observed before.”
“After that, there’s still a lot of mystery as to what’s going on and in many labs, including my own, we continue to work on this problem,” Datta said.
Understanding how Covid-19 has warped someone’s sense of smell will be important for scientists to determine how to help them regain it, if it doesn’t come back on its own.
“I had a patient call me the other day and ask what could be done and honestly, I don’t have any good recommendations yet,” Hayes said.