As many as 1.6 million Americans had their sense of smell impaired for six months or longer because of a COVID-19 infection, according to a new study published Thursday in JAMA Otolaryngology-Head & Neck Surgery.

The authors warn that anosmia – a lingering loss of smell – is an “emerging public health concern.” At least 700,000 Americans have experienced long-lasting anosmia due to the virus, they estimate.

The Covid-19 pandemic has brought on an "emerging public health concern" of people losing their sense of smell, according to new research https://t.co/k3K81oXVEw

— CNN (@CNN) November 19, 2021

“The loss of olfaction has been associated with decreased general 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,” according to the study.

Jay Piccirillo, a otolaryngologist at Washington University in St. Louis and an editor at JAMA Otolaryngology, told Gizmodo that most COVID-19 patients who lost their sense of smell recovered it within two weeks. But, he added, about 5% of all anosmia cases will lose some or all of their sense of smell permanently.

“The long-term disease burden from this, we’re literally going to be dealing with this for decades,” John Hayes, director of the Sensory Evaluation Center at Penn State’s College of Agricultural Sciences, told CNN.

CNN adds:

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.

Red eyes, ringing ears, sensitivity to light, trouble hearing: although a loss of taste and smell have become well-known sensory symptoms of COVID, accumulating research suggests that vision and hearing are also frequent targets. https://t.co/arcZPkcD1K

— Scientific American (@sciam) November 17, 2021

Gizmodo provides important context:

…permanent anosmia may be one of the most distinct lifelong consequences of infection. A recent study by French researchers this month even found that anosmia may be the long-term symptom most likely to be associated with a lab-confirmed case of covid-19. Long after the pandemic has faded away, many people will no longer be able to enjoy certain basic pleasures of life, like a delicious meal or the familiar scents of loved ones.

A recent article published by The Cleveland Clinic outlines potential treatments for COVID-induced loss of smell, including “olfactory training,” steroid use, and surgery.