A new study has found that approximately one in every 20 people who catch Covid suffer from long-term issues with their smell or taste.
This could mean that millions of people around the world may have suffered smell and taste problems for at least six months following a Covid infection.
Loss or change of sense of smell or taste can make people suffer “severe distress”, academics said as they urged health systems to be prepared to support people who often feel “isolated” when dismissed by clinicians.
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They said daily activities such as smelling coffee and testing the flavour of food can become “disgusting and emotionally distressing”.
The new study, published in The BMJ, reviewed data from 18 studies involving 3,699 patients.
Based on the data, the team of international researchers, including some from the UK, used modelling to estimate how many people go on to suffer from altered taste or smell for at least six months after a Covid infection.
They concluded that an estimated 5.6% of Covid patients suffer smell dysfunction for at least six months and 4.4% have an altered taste.
In July there had been some 550 million infections worldwide, which means 15 million may have had lasting smell problems and 12 million patients had taste problems for at least six months, the authors estimated.
Women were less likely to recover their sense of smell and taste, and patients who suffered the most from the initial infection were also more likely to have lasting effects.
In a linked editorial, a team of Italian academics wrote that people “only realise the importance of smell when it is lost” and they can be “severely distressed” when they lose these senses.
“Loss of smell and taste adversely affects quality of life by depriving those affected of several everyday pleasures and social bonds,” the team, led by Paolo Boscolo-Rizzo from the University of Trieste, wrote.
“People can also experience anorexia, food aversions, malnutrition, anxiety, and depression,” they added.
They highlighted that parosmia – the experience of a distorted sense of smell – means that for many this “transforms a pleasant odour into an unpleasant one”.
This means that “daily activities such as smelling coffee and sensing the flavour of food can become disgusting and emotionally distressing”.
What support is in place for those with long Covid?
NHS England has set out its ‘Long Covid Action Plan’ for thousands of people with ongoing symptoms.
Under the plans, people will be able to access services closer to home and be given an initial assessment within six weeks at a specialist clinic.
It is hoped that the £90 million service will reduce the need for a patient to return to their GP for multiple different symptoms.
The money will be used to fund 90 specialist long Covid clinics, 14 hubs for children and young people and investment in training and guidance to support GP teams in managing the condition.