One of the hallmarks of a Covid infection is loss of the sense of smell, which often affects the sense of taste too.
Not that Covid is the first virus to do this – many upper respiratory viruses do the same thing, including the flu virus.
Most people regain their sense of smell in a few weeks but some never do. Smell loss is due to damage to the sensors in the nose lining. But is there a remedy to help them heal?
Previous research from Germany has shown the potential benefit of vitamin A, and researchers at the University of East Anglia and James Paget University Hospital will now explore how this treatment helps repair damaged nose tissues.
Smell-loss expert Prof Carl Philpott from UEA’s Norwich Medical School, said: “The huge rise in smell loss caused by Covid-19 has created worldwide demand for treatment.
And around one in 10 people who experience smell loss report their sense of smell has not returned to normal four weeks after falling ill.
“It’s a big problem, and our previous research has shown the impact of smell loss – including depression, anxiety and isolation, as well as risk of danger from hazards such as gas and spoiled food, and changes in weight due to reduced appetite.
“We want to find out whether there is an increase in the size and activity of damaged smell pathways in patients’ brains when they are treated with vitamin A nasal drops.
“This would show recovery of the damage caused by common viral infections, including Covid-19, in the nose.”
Patients will either receive a 12-week course of nasal vitamin A drops or inactive drops, and have their brains scanned before and after treatment.
The scans will be compared to those of a control group who haven’t been treated with vitamin A drops.
Prof Philpott said: “The patients will be smelling distinctive odours, roses and rotten eggs, while special MRI brain scans are taken.
“We will look for changes in the size of the olfactory bulb – an area above the nose where the smell nerves join together and connect to the brain.
“We will also look at activity in areas of the brain linked to recognising smells,” he added.
To take part in this trial, patients need to be referred to The Smell and Taste Clinic at the James Paget University Hospital by their GP.
Recruitment is expected to begin in December 2021.