About 11 to 15 per cent of women seem to have issues with smell and taste at least six months after having covid-19 if they had problems with the senses during the initial illness, compared with just 1 to 3 per cent of men
27 July 2022
Women who experience problems with smell and taste when they have covid-19 are more likely to have long-lasting issues with the senses than men.
Benjamin Tan at the National University Hospital in Singapore and his colleagues have analysed 18 clinical studies from around the world to investigate the prevalence of smell and taste problems caused by covid-19 and how long they last. The studies recorded people’s symptoms over the course of their recoveries and included a total of 3699 people.
Between 10.8 per cent and 14.7 per cent of women were likely to have issues with smell and taste that lasted for at least six months if they experienced initial problems with the two senses after developing covid-19. The equivalent figure for men was between 1.4 and 2.9 per cent.
Tan says there are several possible reasons for this. “Healthy women already have better senses of smell than healthy men,” he says. “This may mean that they may be more aware of a decrease in their smell and taste abilities.”
Another factor could be the hormone oestrogen, which women tend to have more of. It is known to promote the production of the ACE-2 protein, which the SARS-CoV-2 virus that causes covid-19 uses to enter cells, says Tan.
The team also found that people who had symptoms of nasal congestion because of covid-19 were more likely to get long-lasting issues with their sense of smell. It is unclear why this is the case, but Tan says it could be due to how the virus invades the nasal lining to cause inflammation.
“The stronger the inflammatory response, the more congested the nose might become,” he says, and the greater the damage to the cells of the olfactory neurons is likely to be. This may be more difficult to recover from, he adds.
Tan says the team didn’t have enough data to tease out whether there are any differences in covid-19 symptoms for people from different ethnicities or other groups.
“The results seem quite plausible,” says Shamil Haroon at the University of Birmingham, UK. “The finding that nasal congestion increases the risk of persistent smell and taste dysfunction is interesting because it is potentially treatable.”
“There is a hypothesis that some long covid symptoms are being driven by overactivity of mast cells, which can cause nasal congestion, and this could potentially be treated with antihistamines and/or nasal steroids,” says Haroon.
Journal reference: BMJ, DOI: 10.1136/bmj-2021-069503
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