Long-Term Smell, but Not Taste, Deficits Seen After COVID-19

WEDNESDAY, May 1, 2024 (HealthDay News) -- Olfactory dysfunction, especially for smell, is more common in individuals with prior COVID-19 versus individuals with no history of infection, with deficits varying by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant type, according to a study published online April 23 in JAMA Network Open.

Ryan Sharetts, from University of Pennsylvania in Philadelphia, and colleagues used self-administered psychophysical tests, the 53-item Waterless Empirical Taste Test (WETT) and the 40-item University of Pennsylvania Smell Identification Test (UPSIT), to investigate the association of COVID-19 with long-term outcomes in taste and smell function. The analysis included 340 individuals with and 434 individuals without prior COVID-19 (recruited from February 2020 to August 2023).

The researchers found that taste scores did not differ between individuals with and without previous COVID-19 (total WETT age- and sex-adjusted mean score, 33.41 versus 33.46). UPSIT scores were lower in the group with previous COVID-19 versus the group without (mean score, 34.39 versus 35.86), with 30.3 percent of individuals with prior COVID-19 and 21.0 percent of individuals without prior COVID-19 having some degree of dysfunction (odds ratio, 1.64). Smell outcomes varied by the SARS-CoV-2 variant present at the time of infection, with individuals with original untyped and alpha variant infections showing more loss than those with other variant infections. Total to severe smell loss occurred in 23.8 percent of individuals with alpha variant infections, 13.5 percent with the original variant infections, and 2.8 percent of individuals with no COVID-19 history.

"These findings suggest that long-term taste loss perceived by many patients with COVID-19 likely reflects the loss of flavor sensations from odorant molecules reaching a damaged olfactory epithelium via the nasopharynx rather than the taste buds," the authors write.

One author disclosed financial ties to Sensonics International, the manufacturer of the smell and taste tests used in this study.

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