How to regain your smell and taste after Covid
Potential treatments include ‘smell training’
Millions of people worldwide are trying to adapt to life without smell and taste after being infected with Covid-19.
For the majority, this olfactory dysfunction lasts for just a couple of days or weeks, but some are still suffering months after contracting the virus. A study last year found that between 700,000 and 1.6m people in the US had lost or had a change in their sense of smell for more than six months after having Covid.
The “precise cause” of sensory loss related to the coronavirus is not known, said Sky News, but experts believe it is connected to “damage to infected cells in a part of the nose called the olfactory epithelium”. Cells in this area of the nasal cavity protect olfactory neurons that enable humans to smell.
A study published in the Nature Genetics journal this week suggests that genetics play a key role in determining whether a person loses or experiences a change in their sense of smell and taste after being infected with Covid-19.
The analysis of DNA data on nearly 70,000 adults in the UK and the US with Covid found that those with “certain genetic tweaks” on a chromosome near two olfactory genes, called UGT2A1 and UGT2A24, were 11% more likely to lose the ability to smell or taste than people without the changes, explained Science News.
The researchers suggested that the genetic variants “could affect how the two genes are turned on or off to somehow mess with smell during an infection”, the site said.
A related and lesser-known symptom of Covid is parosmia, where people experience smell distortion after contracting the virus. Certain odour molecules can act as triggers, which vary from person to person but often include flavours like coffee, meat and egg.
According to Fifth Sense, a charity for people affected by smell and taste disorders, an estimated 25,000 UK adults who have had Covid have been affected by parosmia, which “can mean food gives off an unpleasant odour or taste, such as rotten meat or chemicals”, said the BBC.
Although there is currently no cure for parosmia, Fifth Sense and experts from the University of East Anglia have created an online guide for a “smell training technique” that advocates say may help anyone who has experienced a loss or change in their sense of smell.
The training normally involves sniffing at least four distinctive smells, such as oranges, coffee or garlic, twice a day for several months in order to retrain the brain to recognise different smells.
Another potential treatment for olfactory dysfunction is steroids – anti-inflammatory medicines used to treat a range of conditions from eczema to arthritis. Along with suppressing inflammation, they work by reducing the activity of the immune system.
Although steroids may cause increased appetite, mood changes and difficulty sleeping, they “do not tend to cause significant side effects” if taken for a short time or at a low dose, according to the NHS website.
Experts have argued that smell training is preferable to steroids for people suffering from a lack of smell and taste as a result of Covid. Professor Carl Philpott of the University of East Anglia described smell training as “a cheap, simple and side-effect free treatment option”.
He added that “luckily”, the majority of people who experience smell and taste loss as a result of the virus end up regaining these senses “spontaneously”.