The medical term for having no sense of smell is ‘anosmia’. People can be born with no sense of smell, due to genetic factors, but most lose it later in life, sometimes permanently. Anosmia has many causes, including head injury, dementia, nasal polyps, and even snake bites.
But the most common cause, accounting for up to 40 per cent of cases, is a viral infection. Indeed, one reported symptom of the coronavirus disease COVID-19 is a loss of smell.
It’s not yet known what causes this, but I experienced it for myself when I had a mild case of COVID-19 earlier this year. My sense of smell gradually returned, but even after three weeks, I still couldn’t smell coffee.