Since the COVID-19 pandemic began, many individuals have reported acute loss of smell and taste. In order to better characterize all patients with these symptoms, a longitudinal national survey was created. Since April 10, 2020, 549 completed the initial survey, with 295 completing 14-day, and 202 completing 1-month follow up surveys. At 1-month follow-up, 71.8% reported a return to "very good" or "good" smell, and 84.2% reported a return to "very good" or "good" taste. Chemosensory changes are a cardinal sign of COVID-19. Fortunately, our data, representing a large longitudinal study of patients experiencing smell and taste losses during the COVID-19 pandemic, indicates that the majority appear to recover within a month.
Since the COVID-19 pandemic began, many individuals have noted acute loss of smell and/or taste, although not all patients with these symptoms are tested for COVID-19. To better characterize all patients with these rare symptoms, a national survey was created. Over 13 days in April 2020, a total of 220 people completed the survey in its entirety, representing a wide geographic distribution across the United States. Of the 220 respondents, 93 (42%) were diagnosed with COVID-19, and 127 (58%) were not. A total of 37.7% of respondents reported changes in smell/taste as the initial or sole presentation of their condition. Most but not all patients had other symptoms suggestive of COVID-19 at the time of chemosensory loss. Despite its inclusion as a major symptom of COVID-19 by the CDC (Centers for Disease Control and Prevention), respondents with additional CDC-defined symptoms associated with COVID-19 were statistically more likely to be tested/diagnosed than those without.
Objective
To determine which factors (demographic, symptoms, comorbidities, and treatments) are associated with recovery of smell in patients with COVID-19 associated olfactory loss.
Study design
Prospective, longitudinal questionnaires.
Setting
National survey.
Methods
A longitudinal web-based nationwide survey of adults with COVID-19 associated smell and taste loss was launched April 10, 2020. After completing an initial entry survey, participants received detailed follow-up questionnaires 14 days, and 1, 3 and 6 months later.
Results
As of June 25, 2021, 798 participants met study inclusion criteria and completed 6-month questionnaires. Of demographic characteristics only age <40 years was positively associated with smell recovery (
p
< .003). Of symptoms, difficulty breathing was negatively associated with smell recovery (
p
< .004), and nasal congestion positively associated with smell recovery (
p
< .03). Of pre-existing comorbidities only previous head injury (
p
< .017) was negatively associated with smell recovery. None of the queried medications used to treat COVID were associated with better rates of smell recovery.
Conclusions
Age <40 and presence of nasal congestion at time of COVID-19 infection were predictive of improved rates of smell recovery, while difficulty breathing at time of COVID-19 infection, and prior head trauma predicted worsened rates of recovery. Further study will be required to identify potential mechanisms for the other observed associations. Such information can be used by clinicians to counsel patients suffering COVID-19 associated smell loss as to prognosis for recovery.
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