Few of COVID-19’s peculiarities have piqued as much interest as anosmia, the abrupt loss of smell that has become a well-known hallmark of the disease. COVID-19 patients lose this sense even without a stuffy nose; the loss can make food taste like cardboard and coffee smell noxious, occasionally persisting after other symptoms have resolved.
Scientists are now beginning to unravel the biological mechanisms, which have been something of a mystery: The neurons that detect odors lack the receptors that the coronavirus uses to enter cells, prompting a long debate about whether they can be infected at all.
Insights gleaned from new research could shed new light on how the virus might affect other types of brain cells, leading to conditions like "brain fog,” and possibly help explain the biological mechanisms behind long COVID-19 — symptoms that linger for weeks or months after an initial infection.