Medical experts in countries hit by COVID-19 are reporting the first tell-tale signs of the virus may be in an unexpected loss in smell.

Ear, nose and throat (ENT) surgeons say loss of smell – as the virus causes swelling in the olfactory mucosa more than other viruses – could be used as a key clinical indicator in otherwise symptom-free carriers of COVID-19.

“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 around the world,” says South Australian specialist Flinders University Professor Simon Carney, from the Southern ENT and Adelaide Sinus Centre.

“While further research is required, loss of smell, or anosmia, has been reported in as many as 1 in 3 patients in South Korea and, in Germany, this figure was as high as 2 in 3 patients,” says the Professor of Otolaryngology (head and neck surgery) at Flinders University.

“An ENT professor in London has reported seeing a dramatic increase in patients with anosmia as their only symptom of COVID-19 infection.”

As Australia struggles to contain the spread of COVID-10, identification of these carriers could help to slow the spread of infection.

“In the UK, ENT surgeons are pushing to have anosmia highlighted as an important symptom that may signify a patient may be an asymptomatic carrier,” says Professor Carney, immediate past president of the Australia and New Zealand Rhinologic Society.

“Australia is in a position to take advantage of these findings overseas to try and ‘flatten the curve’ while we still can.”

Doctors and COVID-19 detection centres could use this subtle sign and unexplained sudden anosmia the testing criteria, he says.

Patients should also consider calling their GP with this early symptom as a precursor for possible treatment.