A pair of ear, nose, and throat doctors (ENTs) in the United Kingdom on Friday published a statement warning doctors that anosmia, or loss of sense of smell, and ageusia, diminished sense of taste, could be symptoms of COVID-19, the disease caused by the new coronavirus.

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However, the researchers qualified their comments, noting the observations are preliminary.

New paper suggests loss of taste, smell may be associated with COVID-19

The statement was published by Claire Hopkins, president of the British Rhinological Society, and Nirmal Kumar, president of ENT UK.

In the statement, the authors cited reports from doctors around the world who observed that anosmia was commonly reported among patients who tested positive for the virus.

"There is already good evidence from South Korea, China, and Italy that significant numbers of patients with proven COVID-19 infection have developed anosmia/hyposmia," the authors write. In South Korea, for instance, anosmia was the major presenting symptom for 30% of 2,000 patients with a confirmed case of the disease, according to the authors.

Further, Hopkins and Kumar note, "There have been a rapidly growing number of reports of a significant increase in the number of patients presenting with anosmia in the absence of other symptoms."  For instance, they point out that Iran, has seen "a sudden increase in cases of isolated anosmia." A similar pattern has emerged in other places hit hard by COVID-19, including the United States, France, and northern Italy.

With these observations in mind, Hopkins and Kumar in the statement say doctors should use personal protective equipment when treating patients with anosmia. They also advise doctors against performing nonessential sinus endoscopy procedures due to the risk of contracting the virus.

Doctors worldwide raise the possibility of new COVID-19 symptoms

Several ENTs in the United States and elsewhere agreed with what Hopkins and Kumar said in their paper.

"I've had colleagues from around the world saying: 'That's exactly what we're seeing.' They've been trying [to raise awareness], but it hasn't been picked up," Hopkins said.

Rachel Kaye, an assistant professor of otolaryngology at Rutgers University, said she first started hearing that loss of sense of smell could be a symptom from colleagues in New Rochelle, New York, one of the centers of the coronavirus outbreak in the United States.

Hendrik Streeck, a German virologist from the University of Bonn, said two-thirds of the more than 100 patients he interviewed with mild cases of the disease reported loss of smell. Another physician in Germany said about half their patients experienced the symptom, which usually presented after other symptoms of the respiratory illness.

The experts hope the statement will encourage people with anosmia to self-isolate to prevent transmission, even if they aren't experiencing other symptoms.

"This week, I saw nine patients that lost their sense of smell, which is unheard of in my practice. They were almost all under 40, and they were all told not to self-isolate," Hopkins said. "We really want to raise awareness that this is a sign of infection and that anyone who develops loss of sense of smell should self-isolate."

Health organizations weigh in

The American Academy of Otolaryngology on Sunday updated its website to say that evidence pointed to anosmia and ageusia, in the absence of sinusitis or allergies, as a symptom of COVID-19 and that the signs should "warrant serious consideration for self-isolation and testing of these individuals."

In addition, the group noted the risk COVID-19 poses to ENTs. "There is evolving evidence that otolaryngologists are among the highest risk group when performing upper airway surgeries and examinations," the American Academy of Otolaryngology's website states. "A high rate of transmission of Covid-19 to otolaryngologists has been reported from China, Italy and Iran, many resulting in death."

But experts at the World Health Organization on Monday said they have yet to confirm loss of smell or taste as a symptom of COVID-19, and some experts argued that the symptom is too common to be used as a warning sign for COVID-19, STAT News reports.

Thomas Hummel, an ENT at the University of Dresden, said, "Many people out there have anosmia. They don't have a good sense of smell. And if you alert all these people that if you have anosmia you need to stay home, there would be many false positives."

On the other hand, Eric Holbrook, director of rhinology at Massachusetts Eye and Ear, said, "[A]nything that gives us a heads-up into who needs to be isolated or tested … might be a good screening tool." He added, "I wouldn't use it alone [to screen patients], but I think if it's added to some of the other symptoms, it adds to the possibility" (Brodwin, STAT News, 3/23; Rabin, New York Times, 3/22; Brice-Saddler, Washington Post, 3/24; Hopkins/Kumar, ENTUK.org, accessed 3/25).