The research published in JAMA Otolaryngology-Head & Neck Surgery estimated that between 700,000 and 1.6 million people in the United States who had Covid-19 lost or had a change in their sense of smell that lasted more than 6 months. This is probably an understatement, said the authors of the University of Washington School of Medicine in St. Louis.
“These data suggest an emerging concern about OD and the urgent need for research that focuses on treatment of COVID-19 COD,” the study said.
“The long-term disease burden of this, we’ve been literally dealing with this for decades,” according to John Hayes, director of the Sensory Assessment Center at Penn State College of Agricultural Sciences. Hayes did not work on that study but did research in the area.
He thinks the estimated number of people in the study with this problem is conservative and the issue could affect many millions more.
“It’s really consistent with appetite and social relationships, how people have lost their sense of smell may not be able to detect if they have a body odor, and can also affect diet,” Hayes said.
Hayes said his research with Covid-19 patients showed they experienced three different types of long-term olfactory disorders.
Some lose or have decreased sense of smell. Some have a sense of smell that is far away, where instead of flowers, for example, someone would smell foul-smelling feet. Others may have what Hayes calls a kind of “ghost limb syndrome” for sense of smell, where people smell things that aren’t actually there, like a constant chemical or burning odor.
Dr. Sandeep Robert Datta, a neurobiologist at Harvard Medical School who studied why people with Covid-19 lose their sense of smell, said this is an important line of research.
“We never really had a formal estimate of how many people struggled with this,” Datta said. “This is a truly unusual event in terms of olfactory dysfunction and an unprecedented consequence of a pandemic that has never really been observed before.”
“After that, there’s still a lot of mystery about what’s going on and in a lot of labs, including mine, we’re still working on this problem,” Datta said.
Understanding how Covid-19 has distorted someone’s sense of smell will be important for scientists to determine how to help them recover it if it does not return on its own.
“I had a patient call me the other day and ask what could be done and honestly, I still don’t have good recommendations,” Hayes said.
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