Two professors in the United Kingdom have issued a statement suggesting the loss of smell can be a symptom of coronavirus COVID-19.
While the most frequent known symptoms of the respiratory illness, which has infected 375,000 people worldwide and killed 16,000, are a fever, shortness of breath, and a cough, the British Association of Otorhinolaryngology (ENT UK) has issued a statement saying some patients are also suffering anosmia, the loss of smell.
A statement signed off by Professor Claire Hopkins, President of the British Rhinological Society, and Professor Nirmal Kumar, President of ENT UK, says there is emerging evidence from South Korea, China and Italy - three centres with some of the largest numbers of COVID-19 cases - that shows COVID-19 patients have developed anosmia.
They say that wouldn't be surprising as other viruses can lead to the sense loss.
In Germany, the statement says, it is reported that two in three confirmed cases have either totally or partially lost their sense of smell, while in South Korea, about 30 percent of cases have anosmia as their "major presenting symptom" in otherwise mild cases.
German virologist Hendrik Streeck told news site Frankfurter Allgemeine that he knew of cases where a mother couldn't smell the full diaper of her child. He said it was unclear when these symptoms appear, but it seemed to be later in the infection.
Possibly more concerning is that the ENT UK statement says there have been reports of a "significant increase" in the number of patients with anosmia without other major symptoms.
"Iran has reported a sudden increase in cases of isolated anosmia, and many colleagues from the US, France and Northern Italy have the same experience. I have personally seen four patients this week, all under 40, and otherwise asymptomatic except for the recent onset of anosmia – I usually see roughly no more than one a month," the statement says.
"These patients may be some of the hitherto hidden carriers that have facilitated the rapid spread of COVID-19. Unfortunately, these patients do not meet current criteria for testing or self isolation."
The statement notes while the increase in reports of anosmia could be a result of the greater attention the virus is given in the media or the result of other strains of coronavirus, "it could potentially be used as a screening tool to help identify otherwise asymptomatic patients".
"There is potential that if any adult with anosmia but no other symptoms was asked to self-isolate for seven days, in addition to the current symptom criteria used to trigger quarantine, we might be able to reduce the number of otherwise asymptomatic individuals who continue to act as vectors, not realising the need to self-isolate."
The ENT UK statement suggests all healthcare personnel wear protective equipment.
Utah Jazz NBA basketball player Rudy Gobert, who has tested positive for COVID-19, tweeted on Sunday that he believed the loss of smell and taste were symptoms and that he had been suffering from this for the last four days.
Simon Carney, a professor of ear, nose and throat surgery at South Australia's Flinders University told Bloomberg that the new information was significant and it was important for it to be in the public domain for health authorities to examine and debate.
"It is these 'silent carriers' who may remain undetected by current screening procedures, which may explain why the disease has progressed so rapidly in so many countries," he said.
The American Academy of Otolaryngology-Head and Neck Surgery said anosmia should be added to the list of screening tools for possible COVID-19 infection.
A statement said patients with this symptom in the absence of other respiratory diseases should be seriously considered for self-isolation and testing. It also suggested dysgeusia, the distortion of taste, be considered a potential symptom.
New Zealand’s Director-General of Health Dr Ashley Bloomfield was questioned about the loss of smell as a symptom at his Tuesday press conference. He said he had read about it and believed it was “an incidental finding” that researchers will follow-up on.
