Smell, taste loss less likely with newer COVID variants: Study

Since the early days of the pandemic, loss of smell and taste have been tied to COVID-19 infection. But a new study shows those telltale traits are much less likely with the Omicron variant than the earlier Alpha and Delta versions of the coronavirus.

The findings are significant in determining whether someone has COVID-19, said lead study author Dr. Daniel Coelho. He is a professor at Virginia Commonwealth University School of Medicine, in Richmond.

"Loss of smell and taste is still a good indicator of a COVID-19 infection, but the reverse is no longer true," Coelho said in a university news release. "Do not think you are COVID-negative just because your sense of smell and taste is normal."

For the study, the researchers analyzed U.S. National Institutes of Health data on more than 3.5 million COVID-19 cases since the start of the pandemic. They pinpointed six-week periods where cases were highest for each variant studied, then compared how many patients were diagnosed with smell and taste loss in these time periods.

Rates of smell and taste loss were 17% for Omicron, compared with 44% for Delta and 50% for Alpha, the investigators found.

The study was published recently in the journal Otolaryngology—Head and Neck Surgery.

"As the pandemic continues and new variants emerge, this is very good news for patients," Coelho said. "We now know that each variant has a different risk factor for associated smell and taste loss, and have reason to believe that newer variants are less likely to impact smell and taste."

The impacts of the loss of smell and taste are "not just about being able to enjoy a fine bottle of wine again; it's about safety and preserving your quality of life," Coelho noted.

Their research shows that more than half of people suffering from smell and taste loss have reported feeling depressed, he said. "Patients with smell loss also have a higher rate of dementia. Fewer people experiencing these symptoms means fewer people being impacted by mood changes and cognitive problems," he explained.

The study also could help efforts to identify what part of the COVID-19 virus causes the loss of smell and taste.

"Unlocking what causes smell and taste loss in the first place will help us better determine how to treat it," Coelho said.

The study authors now plan to study how recovery time from smell and taste loss varies among variants. They added that more research is needed to find out if vaccination status also plays a role in lower rates of smell loss.

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