About 14 years ago, Chrissi Kelly lost her sense of smell after catching a virus in the Czech Republic. Months later, when she still couldn’t smell anything, doctors diagnosed her with anosmia and told her to learn to live with it. But for Kelly, the loss was catastrophic: 'After six months of complete loss, I was just climbing the walls, and I did not feel like myself anymore.'

Researchers estimate that up to 22 percent of the population lives with smell impairments such as hyposmia (partial smell loss) or anosmia (complete smell loss). And many others live with other conditions like phantosmia, in which a person picks up phantom smells, or parosmia, where pleasant scents start to register as highly unpleasant. Yet these conditions have been poorly understood and often minimized by clinicians.

The pandemic changed that. With over 780 million reported cases of COVID-19 since December 2019, the virus brought unprecedented attention—and research interest—to the sense of smell. A 2023 survey published in Laryngoscope found that 60 percent of individuals with COVID experienced smell loss, most temporarily, but some for a longer period.

With millions of noses worldwide malfunctioning at roughly the same time, the virus spurred newfound appreciation for, and research into, this critical sense. As scientists learn more about how the sense of smell operates, evidence is mounting that it is deeply tied not only to quality of life but also to brain health.