EDMONTON -- Four out of five COVID-19 survivors see their sense of smell or taste return within six months of contracting the novel coronavirus, with people under 40 more likely to recover these senses than older adults, according to an ongoing survey of COVID-19 patients conducted by Virginia Commonwealth University (VCU).
Among 798 respondents to the ongoing COVID-19 smell and taste loss survey who had tested positive for the disease and reported a loss of those senses, those who were younger than 40 recovered their sense of smell and taste at a higher rate than those older than 40.
“With our cohort, we did see about an 80 per cent recovery rate in a six-month period or longer,” Evan Reiter, co-investigator of the study, said in a press release. “However, 20 per cent is still a lot of people, given the millions that have been afflicted with COVID-19.”
Referred to by the medical community as Parosmia, the condition is caused when receptor cells in the nose don't detect and translate odours to the brain properly. It can happen after a bad cold or sinus infection, head injury and seizures.
Parosmia has also been associated with a complete loss of smell and taste, called anosmia, that has become a hallmark sign of COVID-19.
Previous studies have found that smell loss can occur in 40 to 68 per cent of COVID-19 cases, most often popping up in mild to moderate cases, and it strikes more women than men.
The results, published in the American Journal of Otolaryngology last month, suggest that patients with a history of head injuries were less likely to recover their sense of smell.
Recovery was also less likely in those who experienced shortness of breath while sick with COVID-19. Those who experienced simple nasal congestion, on the other hand, were more likely to regain their sense of smell.
“Increased likelihood of recovering smell in subjects with nasal congestion stands to reason simply because you can lose your sense of smell because you’re badly congested and odors can’t get into your nose,” Reiter said in the release.
“Certainly, a subset of those people who are congested might have just lost their sense of smell because they were badly congested, rather than because of nerve damage due to the virus, as in other cases.”
Researchers at VCU began tracking COVID-19 patients in April 2020 following widespread reports of patients experiencing a loss of taste and small. Nearly 3,000 people over the age of 18 in the U.S. have participated in the study, which tracks symptoms over time.
In April, VCU researchers released survey data that suggested 43 per cent of participants reported feeling depressed and 56 per cent reported a decreased enjoyment of life without their sense of taste and smell.
Unsurprisingly, the most common quality-of-life concern was reduced enjoyment of food, with 87 per cent of respondents saying it was an issue. However, complete loss of appetite and unintentional weight loss continue to pose challenges for those patients.
“The more we learn from those who’ve been affected, the better we can advise their health care providers and even individuals themselves on how to manage those symptoms,” Daniel Coelho, lead author, wrote in a press release.
“Through this study, we continue to gain a clearer picture of the risks COVID-19 poses to quality of life, safety and long-term health and well-being while seeking answers on treatment.”
Thanks to COVID-19, much attention has been turned to finding a solution for those suffering from anosmia – a mission VCU researchers have been dedicated to since 2018.
Coelho and senior author of the study Richard Costanzo have been working on an early-stage development of an implant device to restore sense of smell modelled after a cochlear implant.
In those with hearing loss, a cochlear impact bypasses damaged parts of the ear to deliver electrical signals to the auditory nerve, re-routing the signal to the brain. Coelho and Costanzo theorized they could develop a similar device that would use small gas sensors to detect odour molecules and use electrical signals to stimulate the olfactory bulb, producing smell.
While the device is still merely a prototype, researchers are optimistic that, when operational, it could be a source of hope for those with lasting smell loss.
