Millions of people around the world may have long-term odor or taste problems as a result of Covid-19, with women more likely to be affected, a study suggests.
According to research published in the BMJ, about 5% of adults infected with the coronavirus may develop long-term changes in their sense of smell or taste.
With more than 550 million confirmed Covid-19 cases to date, that means there may be long-term odor deficits for at least six months after infection for 15 million people and taste problems for 12 million (with an unknown overlap of those affected by both). suffering). .
Given the devastating effect that loss of smell and taste can have on quality of life and well-being, it will have a huge impact on global health, say the team of international researchers.
Loss or alteration of sense of smell or taste can lead to “severe stress,” they say, and they advocate that health systems be better prepared to support people who often feel “isolated” when discharged by clinicians.
Daily activities such as smelling coffee and testing the taste of food can become “disgusting and emotionally distressing,” experts say.
The study reviewed data from 18 studies involving 3,699 patients. Using models, the researchers estimate how many people continue to suffer from an altered taste or smell for at least six months after a Covid-19 infection.
They concluded that an estimated 5.6% of patients have a sense of smell for at least six months and that 4.4% have altered taste.
Women were less likely to recover their sense of smell and taste than men, and patients with greater initial severity of smell loss and those with nasal congestion were less likely to recover their sense of smell.
One female patient told the researchers that 27 months after her initial infection, she had yet to regain her sense of smell.
The researchers acknowledge several limitations of the study. The studies analyzed varied in quality and were based on self-report, although they say this “may overestimate recovery, suggesting that the true burden of olfactory dysfunction is even greater.”
They say that while most patients are expected to recover their sense of smell or taste within the first three months, “a large group of patients may develop long-term dysfunction that requires timely identification, personalized treatment, and long-term follow-up.”
Prof Danny Altmann, a professor of immunology at Imperial College London, who was not involved in the study, said: “This is a strong and important study, warning us once again of the difficulties inherent in mapping the extent of long-term damage caused by Covid-19.
“The authors performed a rather rigorous meta-analysis across different cohorts, modeling the time to recovery of taste and smell. It goes without saying that taste and smell problems are not trivial for quality of life.
“This is part of a wider discussion on how we are assessing and tackling the ongoing changes collectively referred to as Long Covid. Studies like this alert us to the hidden burden of people who suffer from persistent symptoms, but who may not have found it worthwhile to contact their GP on the assumption that there wasn’t much that could be done.”