TOKYO -- Loss of the ability to smell and taste can be an early sign of coronavirus infection, according to a growing number of reports from around the world.
More than two in three confirmed COVID-19 patients in Germany had anosmia -- the inability to smell -- and China, South Korea and Italy have also reported significant numbers of cases, according to a statement by ENT U.K., an organization for ear, nose and throat specialists.
In South Korea, "30% of patients testing positive have had anosmia as their major presenting symptom in otherwise mild cases," the statement said.
The World Health Organization has "seen quite a few reports" about this phenomenon, but "this is something that we need to look into to really capture if this is one of the early signs and symptoms of COVID-19," Maria van Kerkhove, technical lead for COVID-19 at the organization, said in a briefing Monday.
The American Academy of Otolaryngology set up a website Thursday where doctors can report such cases. Japanese Deputy Chief Cabinet Secretary Akihiro Nishimura told reporters Friday that Japanese organizations are also gathering information.
The novel coronavirus appears to replicate more in the nose than in the throat. "It may be that the virus infects olfactory cells deep within the nose, impairing the sense of smell," said Norio Sugaya, head of the infection control center at Keiyu Hospital in Yokohama.
The ENT UK statement suggested that loss of smell "could potentially be used as a screening tool to help identify otherwise asymptomatic patients."
But this alone is unlikely to prove a reliable indicator. "Even with a normal cold, [patients] can lose their sense of smell, affecting their sense of taste," said Mitsuyoshi Urashima, a professor of molecular epidemiology at Jikei University School of Medicine in Tokyo.
The virus is known to present with a variety of symptoms depending on the patient. A study of 56,000 cases by a joint WHO-Chinese research team released in late February reported fever in nearly 90%, fatigue in about 40% and shortness of breath in just under 20%.