New Delhi: Loss of smell caused by Covid-19 may last for years, even when patients do not notice it, according to new research.
The study, conducted by the US National Institutes of Health and New York University Langone Health, examined 3,535 men and women using a 40-odour test to assess the link between coronavirus infection and hyposmia, or reduced sense of smell. It is the largest study of its kind to employ a formal clinical test, and the findings were published in the journal JAMA Network Open.
Researchers found that 80 per cent of people who reported changes in their sense of smell after Covid-19 scored poorly on scent-detection tests taken about two years later. Among them, 23 per cent were severely impaired or had completely lost the ability to smell.
Surprisingly, 66 per cent of participants who did not report any problems also scored abnormally low in the evaluations. “Our findings confirm that those with a history of Covid-19 may be especially at risk for a weakened sense of smell, an issue that is already underrecognized among the general population,” said study co-lead author Leora Horwitz, professor at NYU Grossman School of Medicine.
The study also found that 60 per cent of uninfected participants who had no complaints about smell performed poorly on the test.
The researchers suggested that health providers consider routine smell testing as part of post-Covid care. Experts are also exploring potential treatments to restore olfactory function, including vitamin A supplements and training exercises designed to “rewire” the brain’s response to odors.