Once a hallmark sign of many COVID-19 cases — sometimes more reliable than even flu-like symptoms at sniffing out people infected by the virus early in the pandemic — was the sudden loss of smell and taste. But growing research suggests this symptom has become far less common, with only a small fraction of new patients reporting it last year.
The findings come from analysis of a sweeping dataset of medical records gathered by the National Institutes of Health for COVID-19 researchers from around the country.
“In the past, people were quite aware, if they had a cold and they lost their sense of smell, that they potentially had COVID. Whereas now, you really can’t tell,” Dr. Evan Reiter, medical director of VCU Health’s Smell and Taste Disorders Center, told CBS News.
Reiter led the study, which was published in May in the journal Otolaryngology-Head and Neck Surgery, examining odds of patients with COVID-19 also reporting loss of smell and taste.
While the symptoms known as chemosensory loss occurred in an estimated 50% of cases early in the pandemic, the latest research suggests a prevalence of just 3% to 4% in more recent Omicron waves.
The study is among the latest to illustrate how the symptoms inflicted by the virus have changed, as new variants have emerged and immunity from infections and prior vaccinations offer defenses that early patients lacked.
Researchers from University College London reported in a study out last week that the proportion of cases reporting loss of taste or smell had significantly decreased after the Omicron strain emerged in 2021.
As more variants of concern emerged, “SARS-CoV-2 symptomatology gradually resembled that of other respiratory symptoms. The more contagious Omicron strains were significantly associated with an increase in cough and sneezing,” that study’s authors wrote in the journal Scientific Reports.