Understanding COVID-19-Related Smell Disturbance

The annual infectious disease conference, IDWeek , hosted by the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, and the Pediatric Infectious Diseases Society took place last week. One recurring theme of the meeting was research on the novel virus COVID-19 that caused the pandemic in 2020.

At that time, outcomes for patients infected with COVID-19 were somewhat unpredictable. Scientists were learning in real time what makes COVID-19 different from similar illnesses. A common symptom shared by many people who had a COVID-19 infection, especially in those early days, was changes in taste and smell that persisted for quite some time after the infection cleared.

To gain insight into this symptom, Ashish Bhargava, MD, and colleagues conducted a study to explore the prevalence of and risk factors associated with smell disturbances after COVID-19 infection. They presented their findings at IDWeek. Early cases of COVID-19 had a high rate of smell disturbance, with 40% to 45% of patients reporting anosmia, hyposmia, or phantosmia.

This number dropped dramatically when omicron became the dominant strain, with smell disturbance only reported in 4% to 12% of cases. Although most patients recover their sense of smell, a small subset of 5.6% experience persistent smell disturbance. National Health Interview Survey (NHIS) data from 2021 showed that even more patients were affected by smell disturbance.

More than 60% of adults reported loss of smell with COVID-19 infection, and 24.1% experienced only partial recovery. Dr. Bhargava and colleagues conducted a study to see how these outcomes evolved after the pandemic using data from the 2024 NHIS.

Their secondary analysis included adults aged 18 and older who had a COVID-19 infection at least once. The researchers used the Statistical Package for the Social Sciences (IBM) to analyze the data and multivariable logistic regression to identify the factors associated with smell disturbance related to COVID-19 infection.

How Smell Disturbance Evolved With COVID-19 After the Pandemic Dr. Bhargava and colleagues found that 38% of adult respondents to the 2024 NHIS reported smell disturbance with a prior COVID-19 infection, which is significantly lower than the 60.5% who reported the same symptom in the 2021 NHIS.

Through their analysis, they found that several factors increased the risk for smell disturbance: Female sex Younger age Hispanic ethnicity Education below master’s level Poorer health Depression Weakened immune system resulting from a health condition They also identified several factors that lowered the risk for smell disturbance with COVID-19 infection, including vaccination , metropolitan residence, and Black or other race.

Among the respondents who did experience smell disturbance, 82.8% fully recovered and 15.1% had a partial recovery. The remaining 2%, representing about 2 million Americans, reported no improvement in their sense of smell. Clinical Implications Dr.

Bhargava and colleagues conclude that smell disturbance still presents a postpandemic burden for those who have been infected. They also suggest that those at higher risk for smell disturbance “may warrant attention in post-pandemic care.” This study has several limitations, including self-reporting of smell disturbance resulting from COVID-19 infection by NHIS respondents.

These outcomes were not assessed, and the cross-sectional design can’t establish causality related to COVID-19 infection and smell disturbance. However, these data can help drive forward future studies in COVID-19–associated smell disturbance. References Bhargava A, et al.

IDWeek 2026. Poster No. P-393.