About 25% of those with COVID-19 only partially recover taste or smell, or never do

Key takeaways:

• Among patients with COVID-19 who lost smell or taste, 3.1% and 2.6% never fully recovered their senses, respectively.
• Research linking sensory loss and COVID-19 may bolster support for evidence-based treatment.

Approximately one-quarter of adults who lost taste or smell following SARS-CoV-2 infection reported partial or no recovery of their senses, a study published in The Laryngoscope found.

According to Margaret B. Mitchell MD, MS-HPEd, a third-year resident in otolaryngology at Harvard Medical School and lead study author, and colleagues, prior research identified olfaction and gustatory dysfunction as symptoms of COVID-19, but those studies have been small and showed significantly varying prevalence of sensory loss in patients.

As a result, “we wanted to quantify the national impact of smell disorders resulting from [COVID-19],” study researcher Neil Bhattacharyya, MD, FACS, a professor of otolaryngology at Mass Eye and Ear, said in a press release. “With [these] data we can understand, in big numbers, how many people lost their sense of smell or taste due to [COVID-19] and how many people never fully recovered those senses.”

The researchers analyzed data from the 2021 National Health Interview Survey, which included survey responses from 29,696 adults. The survey inquired whether patients had loss sense of odors or taste and — in the event of sensory loss — what their recovery status was.

Overall, 60.5% and 58.2% of respondents with COVID-19 reported losses in smell or taste, respectively.

“This corresponds to 21.5 million and 20.7 million adults affected with COVID-19-associated loss of smell and taste, respectively, since the pandemic began,” Mitchell and colleagues wrote.

They added that the risk of losing taste or smell was greater the more severe the case of COVID-19 was.

Among patients who lost smell, 72.2% fully recovered, whereas 24.1% only saw a partial recovery and 3.7% never recovered at all.

Meanwhile, 76.8% of patients that lost taste fully recovered, 20.6% partially recovered and 2.6% never fully recovered.

“When olfactory or gustatory loss was present, severity of overall symptomatology was negatively associated with both smell and taste recovery,” the researchers wrote.

Mitchell and colleagues pointed out that although the findings may be useful for providers when consulting patients on sensory recovery, practitioners may still experience challenges “given lack of clear treatment guidelines.”

“Even a recent expert consensus had ambiguous recommendations: while intranasal steroids and sensory training was recommended, it is unclear whether oral steroids or other therapies are of benefit,” they wrote.

However, the strong associations between severe COVID-19 symptomatology and both smell and taste loss and lower odds of sensory recovery “bolsters support not only for vaccines but also other available treatments, such as Paxlovid, which likely decrease overall disease burden,” Mitchell and colleagues wrote.

The study had several limitations. Because the data were self-reported, patients may have had trouble distinguishing dysfunction of one sense from the other. Also, data regarding rates of recovery beyond 2021 and whether patients who reported partial recovery went on to fully recover were also not available.

Ultimately, “the value of this study is that we are highlighting a group of people who have been a bit neglected,” Bhattacharyya said. “Losing your sense of smell or taste isn’t as benign as you may think. It can lead to decreased eating for pleasure and, in more extreme cases, it can lead to depression and weight loss.”

References:

• Mitchell M, et al. Laryngoscope. 2023;doi:10.1002/lary.30802
• Millions of patients do not have full recovery of smell or taste senses after COVID infection, study finds. https://www.masseyeandear.org/news/press-releases/2023/06/millions-of-patients-do-not-have-full-recovery-of-smell-or-taste-senses-after-covid. Published June 13, 2023.