In a new study, researchers describe the loss of sense of smell due to COVID-19 as a "growing public health concern." File photo by Kevin Dietsch/UPI | License Photo
Nov. 18 (UPI) -- Up to 1.6 million people in the United States could develop a long-term inability to smell as a result of COVID-19 infection, potentially creating a new public health challenge, an analysis published Thursday by JAMA Otolaryngology-Head & Neck Surgery estimated.
Although the majority of people who lose their sense of smell because of the virus regain it within a few weeks, nearly one in 10 may see it persist for six months or more, the data showed.
A compromised sense of smell has been linked with reduced "quality of life, impaired food intake, inability to detect harmful gas and smoke, enhanced worries about personal hygiene, diminished social well-being and the initiation of depressive symptoms" in earlier studies, the researchers said.
As a result, the researchers described the increase in numbers of people with chronic olfactory dysfunction as a "growing public health concern of COVID-19."
"We can expect a dramatic increase in the number of Americans suffering long-term olfactory dysfunction [inability to smell]," study co-author Dr. Jay F. Piccirillo told UPI in an email.
And, "unfortunately, there are no known treatments or behaviors that can minimize the risk of chronic olfactory dysfunction," said Piccirillo, a professor of otolaryngology at Washington University School of Medicine in St Louis.
More than 13 million adults age 40 and older in the United States have "measurable" issues with their sense of smell, the National Institute on Deafness and Other Communication Disorders estimates.
The most common causes include neurological disorders, such as Parkinson's disease, head injuries, stroke and brain tumors, according to the institute.
In addition, loss of sense of smell is considered an early warning sign for dementia and stroke, and it is far more common in older adults than in younger people.
Loss of the sense of smell, is considered a key symptom of COVID-19 and is more common in those with severe disease, according to the Centers for Disease Control and Prevention.
It also is frequently reported among people with persistent symptoms of the virus, or "long" COVID-19, based on earlier studies.
Because the virus affects a younger demographic group than other causes, "the lifelong burden of olfactory dysfunction will be much greater," according to Piccirillo and his colleagues.
For their estimates, the Washington University School of Medicine researchers used COVID-19 case data for the United States from the COVID-19 tracking project.
The researchers estimated the number of people who experienced loss of the ability to smell as a result of the virus based on data from a separate analysis, which found that between 30% and 75% of those infected lose that ability.
They then calculated figures for those with chronic, or persistent, olfactory dysfunction based on recovery rates for loss of sense of smell due to COVID-19 ranging from 93% to 98% from another study.
Based on their analysis, between 170,000 and 1.6 million people in the United States could develop chronic issues with their sense of smell as a result of infection with the virus, the researchers said.
"[Our] data suggest an emerging public health concern [as] chronic olfactory dysfunction is associated with increased risk for exposure to toxic fumes, decreased appetite and decreased overall quality of life," Piccirillo said.