Smell and taste dysfunction may persist in 27 million COVID cases

Long-term sensory or taste dysfunction can affect approximately 27 million people worldwide infected with SARS-CoV-2, a meta-analysis of parametric treatment modeling shows.

An estimated 5.6% and 4.4% of COVID-19 patients may develop persistent self-reported sensory and taste dysfunction, respectively, of 15 million and 12 million worldwide as of July 2022. The case was reported by Song Tar Toh and MBBS of the National University. Singapore, and colleagues.

They wrote that women are less likely to restore odors and taste BMJ.. Patients with COVID and those with stuffy nose, who had a high initial severity of dysfunction, were less likely to recover their sense of smell.

Changes in the sense of smell and taste are very prevalent in patients with COVID-19, with an average of 40% -50% of people reporting these symptoms worldwide, the researchers said.

Loss of odor and taste can reduce quality of life and increase the burden of long-term COVIDs, Toh said.

“Even if there were many affected people around the world before the pandemic, many wouldn’t have access to or know that help was available,” he said. Today’s MedPage.. “The pandemic has brought this important medical issue to the attention of doctors and patients.”

Paolo Boscolo-Rizzo, MD and colleagues at the University of Trieste, Italy, say the health care system may not be in place for the scale of this task. Ancillary editorial..

“Health leaders, policy makers, and research funders recognize the extraordinary importance of superior chemosensory function for human well-being, allocate appropriate resources to support chemosensory research, and smell. And it is necessary to maintain a medical professional who faces a large number of patients with sensory dysfunction, “they wrote.

The editors pointed out that there are few evidence-based options for treating chemosensory disorders. “Smell training, which begins as soon as possible after the onset of symptoms, is the only disease-specific intervention that has evidence of efficacy in treating post-infection sensory dysfunction,” they said.

The mechanism of COVID-induced sensory loss is unknown, but may provide a stronger basis for the development of new therapeutic strategies, Boscolo-Rizzo and colleagues added.

“Although the involvement of the olfactory bulb and the central sensory pathway cannot be ruled out, most evidence indicates a virus that targets the sustentacular cells of the sensory neuroepithelium,” they write. “These cells (not the sensory neurons) express the molecular structure required for viral entry.”

Toh’s group analyzed 18 observational studies of adults with COVID-related odor and taste changes and included 3,699 patients in the meta-analysis. Four studies were conducted in a community environment and 14 studies were conducted in a hospital environment. The risk of bias was low to moderate and the quality of the evidence was medium to high.

Researchers used treatment modeling to estimate self-reported sensory and taste recovery rates and identify key factors associated with duration and likelihood of recovery. Modeling shows that persistent self-reported sensory dysfunction occurs in an estimated 5.6% (95% CI 2.7% -11.0%) of patients and taste dysfunction in 4.4% (95% CI 1.2% -14.6%). It was predicted that there was a possibility of doing so. Sensitivity analysis suggested that these may be underestimated.

Patient data for the time to the reconstructed event showed that recovery rates increased over time. At 30, 60, 90, and 180 days, approximately 74%, 86%, 90%, and 96% of patients reported sensory recovery, and 79%, 88%, 90%, and 98% tasted, respectively. Reported recovery. SARS-CoV-2 mutants have not been reported for sensory or taste recovery.

Women were less likely to restore their sense of smell (OR 0.52) or taste (OR 0.31) than men. Patients with high initial dysfunction severity (OR 0.48) or nasal congestion (0.42) were less likely to recover their sense of smell.

Researchers have acknowledged that there are some limitations to the analysis. Studies with different quality, smell, and taste dysfunctions were based on self-reported data. Self-reports can overestimate recovery, suggesting that the true burden of sensory dysfunction is even greater, Toh et al.