New loss of smell (anosmia) is a common symptom of Covid-19, particularly during the first wave of the pandemic. It presents either as an isolated symptom or as part of the constellation of symptoms such as fever, cough, fatigue, shortness of breath, loss of taste (dysgeusia). New onset anosmia during the pandemic was considered equivalent to a positive SARS-CoV-2 RT PCR test.

A new analysis of data published in JAMA Otolaryngology–Head & Neck Surgery reports that nearly 1.6 million people in the United States may lose their sense of smell due to Covid-19. Loss of smell is indicative of mild infection with the majority of patients recovering their sense of smell, though some complain of persistent loss of smell, partial or complete, lasting for 6 months or longer.

The researchers included individuals who tested positive for Covid-19 from January 2020 to March 2021 to estimate the prevalence of chronic olfactory dysfunction. Data was obtained from national data from the COVID Tracking Project. Two factors were incorporated in the analysis - “the incidence of acute COVID-19 olfactory dysfunction at 52.7% (95% CI 29.6-75.2) based on a recent meta-analysis, and the recovery rate from olfactory dysfunction at 95.3% (95% CI 92.6-98.0), based on a prospective study”.

The number of persons who would develop chronic olfactory dysfunction by August 2021 was 712,268 based on intermediate estimates. When low estimates were taken into consideration, this number was 170,238, and based on the highest estimate, the number of persons likely to develop chronic olfactory dysfunction was found to be 1,600,241.

The number of persons with olfactory dysfunction preceding the pandemic was up to 13.3 million adults. The present analysis of data indicates that more than 700,000 and up to 1.6 million patients could develop olfactory dysfunction due to Covid-19 infection. This relative increase of 12% from 5% illustrates Covid-related olfactory dysfunction as a burgeoning public health problem.

Loss of smell has psychosocial outcomes. The consequences of olfactory dysfunction, as shown in previous studies, include reduced quality of life, failure to detect harmful odors like gas and smoke, diminished social well-being and depression. It is also associated with poor nutrition. This study underscores the need for research into finding ways to treat Covid-19 chronic olfactory dysfunction and also minimize the risk. Since anosmia and/or dysgeusia is usually reported by younger patients, the burden of this disease will be much higher.

Reference

1. Khan AM, et al. Growing Public Health Concern of COVID-19 chronic olfactory dysfunction. JAMA Otolaryngol Head Neck Surg. 2021 Nov 18. doi: 10.1001/jamaoto.2021.3379.