On Friday, British doctors issued a warning: adults who’ve lost their sense of smell should stay indoors and avoid contact with other people because they might have mild symptoms of coronavirus infection. Although their preliminary findings are limited, the doctors wrote that such cases that have come to their attention are concerning enough to raise awareness.

Loss of smell and taste linked to mild cases of COVID-19

The warning was issued by two professional associations representing ear, nose and throat doctors in Britain. It urges health care workers to use protective equipment and handle cases of patients who have lost their sense of smell with extra care. Because the virus is known to replicate in a patient’s respiratory tract, they also advise against performing sinus endoscopy procedures on anyone in order to prevent a potential infection with SARS-CoV-2 (the coronavirus that causes COVID-19).

According to the British doctors, at least two ear, nose, and throat specialists from Britain have been infected with the novel coronavirus and are now in critical condition. In Wuhan, China, the epicenter of the pandemic, early reports warned that ear, nose, and throat specialists were getting infected and even died in large numbers under suspicious circumstances. These are not the doctors you go to see when you suspect you might have a coronavirus infection.

“Previously described coronaviruses are thought to account for 10-15% cases. It is therefore perhaps no surprise that the novel COVID-19 virus would also cause anosmia in infected patients,” the ENT UK statement said.

“There is already good evidence from South Korea, China and Italy that significant numbers of patients with proven COVID-19 infection have developed anosmia,” the statement said.”In Germany it is reported that more than 2 in 3 confirmed cases have anosmia. In South Korea, where testing has been more widespread, 30% of patients testing positive have had anosmia as their major presenting symptom in otherwise mild cases.”

The loss of sense of smell is known as anosmia, while losing the sense of taste is called ageusia.

Reports suggest that anosmia may be a common symptom among mild cases of COVID-19, who are among the most likely to spread the disease because they don’t actually feel that sick at all.

In South Korea, 30% of nearly 2,000 patients who tested positive for SARS-CoV-2 experienced anosmia.

In Italy, where there are now twice as many fatalities as in China, doctors also noticed that loss of taste and smell seem to be reliable indicators of a coronavirus infection.

“Almost everybody who is hospitalized has this same story,” Dr. Marco Metra, chief of the cardiology department at the main hospital in Brescia, told the New York Times. “You ask about the patient’s wife or husband. And the patient says, ‘My wife has just lost her smell and taste but otherwise she is well.’ So she is likely infected, and she is spreading it with a very mild form.”

Friday’s joint statement issued by the British ear, nose and throat specialists were echoed by the American Academy of Otolaryngology, which on Sunday stating that:

“Anecdotal evidence is rapidly accumulating from sites around the world that anosmia and dysgeusia are significant symptoms associated with the COVID-19 pandemic. Anosmia, in particular, has been seen in patients ultimately testing positive for the coronavirus with no other symptoms. We propose that these symptoms be added to the list of screening tools for possible COVID-19 infection. Anosmia, hyposmia, and dysgeusia in the absence of other respiratory disease such as allergic rhinitis, acute rhinosinusitis, or chronic rhinosinusitis should alert physicians to the possibility of COVID-19 infection and warrant serious consideration for self-isolation and testing of these individuals.”

There’s quite a large body of evidence that suggests that loss of smell, or anosmia, may be associated with certain respiratory infections.

The good news is that loss of taste and smell seem to mostly occur in mild cases, so that’s actually an indicator that you might not be in danger. Both symptoms disappear after the infection clears up. However, such symptoms should make any person experiencing them extra cautious as to not infect other people.