Loss of Smell Could be Extensive

A research letter published in JAMA Otolaryngology-Head & Neck Surgery on November 19, 2021, found perhaps as many as 1.6 million COVID-19 survivors in the U.S. haven't recovered their sense of smell (olfaction) after more than six months.

The loss of olfaction has been associated with the decreased general quality of life, impaired food intake, inability to detect harmful gas and smoke, enhanced worries about personal hygiene, diminished social well-being, and the initiation of depressive symptoms.

This new analysis put this unknown risk in context.

Before the COVID-19 pandemic, the National Institute on Deafness and Other Communication Disorders estimated that, among adults 40 years or older, measurable olfactory dysfunction (O.D.) was found in up to 13.3 million adults.

The age-specific prevalence of O.D. is 4.2% for individuals between age 40 to 49 years and 39.4% for individuals 80 years and older.

The addition of up to 1.6 million new cases of COD represents a 5.3% to 12% relative increase. In addition, COVID-19 affects a younger demographic group than other causes of O.D.

Thus, the lifelong burden of O.D. will be much more significant for the COVID-19 cohort than for patients in the older age groups.

The incidence of O.D. may be higher among patients who were hospitalized with the SARS-CoV-2 coronavirus as well.

A recent meta-analysis reported the incidence of acute COVID-19 OD as 52.7% (95% CI, 29.6%-75.2%).

However, there is some good news.

A prospective study reported the recovery rate from O.D. to be 95.3% (95% CI, 92.6%-98.0%).

These data suggest an emerging public health concern of O.D. and the urgent need for further research.