How many people have lost their sense of smell because of Covid-19?

In the middle of November 2021, the press made much of reports that up to 1.6 million Americans have persistent smell loss following Covid-19. Some of the headlines were quite sensationalist, so let’s have a quick recap of what we know, and what the article actually said.

What we know

Around 60 percent of people who contract Covid-19 will lose their sense of smell and taste, usually for one or two weeks. In 90 percent of those cases, people will recover naturally and spontaneously as the inflammation caused by the infection subsides.

For one in 10, the experience of smell loss will be more persistent. In these patients, it appears that the virus has damaged the cells that support the olfactory neurons – the receptors in the nose that capture the odour molecules the brain interprets as smells. These cells are designed to grow back, but this does take time. During that recovery process – which can be as long as 24 months in other viruses – the patient will have a reduced ability to smell and may experience parosmia (distorted unpleasant smells).

Many people who lose their sense of smell from a virus have a very good chance of recovering it, particularly if they take up the regular practice of smell training. Smell training needs to be followed daily for up to six months, but all the scientific evidence shows that it’s a worthwhile investment of time as those who smell train are significantly more likely to enjoy a better recovery.

A paper published on 2 November 2021 confirmed that Covid-19 smell loss does not indicate long-term damage to the brain. The cells affected are outside of the brain. 

Most people who lose their sense of smell after a virus can expect it to return in some form, and reports that these people will be anosmic ‘for ever’ are not true. 

What the article said

The purpose of this study was to estimate how many people were affected, and identify how they were affected. 

The authors said, “These data suggest an emerging public health concern of OD [olfactory dysfunction] and the urgent need for research that focuses on treating COVID-19 COD.”

In research, you have to quantify the problem before you can solve it, and this study adds weight to the growing call for more research. Something that we at AbScent whole-heartedly support!

November 30, 2021

Posted in Covid.