An unexpected loss of the sense of smell may be the first sign a person has coronavirus, medical specialists are reporting.

Ear, nose and throat surgeons say a loss of smell, as the virus causes swelling in the olfactory mucosa, could be used as a key clinical indicator in otherwise symptom-free carriers of SARS-CoV-2.

“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,” Flinders University professor and ENT specialist Professor Simon Carney said.

“While further research is required, loss of smell, or anosmia, has been reported in as many as one in three patients in South Korea; and in Germany, this figure was as high as one in two.”