嗅覚（臭覚）の喪失、鼻が全然利かなくなること

the loss of sense of smell

Anosmia, the loss of sense of smell, and ageusia, an accompanying diminished sense of taste, have emerged as peculiar telltale signs of Covid-19, the disease caused by the coronavirus, and possible markers of infection.
https://www.nytimes.com/2020/03/22/health/coronavi...

※theのない用例もある。
“We really want to raise awareness that this is a sign of infection and that anyone who develops loss of sense of smell should self-isolate,” Prof. Claire Hopkins, president of the British Rhinological Society, wrote in an email. “It could contribute to slowing transmission and save lives.”
https://www.nytimes.com/2020/03/22/health/coronavi...

特になし。