key: cord-0818523-hwd9xjnn
authors: Reiter, Evan R.; Coelho, Daniel H.; Kons, Zachary A.; Costanzo, Richard M.
title: Subjective smell and taste changes during the COVID-19 pandemic: Short term recovery
date: 2020-07-08
journal: Am J Otolaryngol
DOI: 10.1016/j.amjoto.2020.102639
sha: 6172d868cf8039e2208dcbcbf97cdb2ef63b2f60
doc_id: 818523
cord_uid: hwd9xjnn

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, 67.1% reported a return to “very good” or “good” smell, and 73.1% 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.

J o u r n a l P r e -p r o o f INTRODUCTION Since the emergence of the COVID-19 pandemic, reports from across the globe suggest that chemosensory loss is amongst the cardinal symptoms of active infection. [1] [2] [3] [4] These findings led major health organizations worldwide to include acute loss of smell and taste as symptoms sufficiently indicative of COVID-19 infection to warrant evaluation. However, little is known about the natural course of these deficits including their potential for recovery. Given significant quality of life and safety impacts of such deficits, prognostic information would benefit patients and their healthcare providers. 5 We present one-month follow-up data from a large, prospectively collected nationwide patient cohort with smell and taste losses during the COVID-19 pandemic.

A web-based survey was opened to patients nationwide with sudden changes in smell and taste since January, 2020. Following consent, patient demographics, associated symptoms, comorbidities, testing status, treatment, and recovery status were collected and managed using REDCap electronic data capture tool. 6, 7 Recruitment was performed through online social media platforms beginning April 10, 2020, with follow-up surveys at 14 days, 1 month, 3 months, and 6 months later. Inclusion criteria were age > 18 years and smell or taste changes since January 1, 2020; those with documented negative COVID-19 tests were excluded. Respondents rated smell and taste as "Very Good", "Good", "Poor", "Very Poor", or "Absent". This study was approved by Virginia Commonwealth University Institutional Review Board (HM20019186). were COVID-19-positive (C+) by testing or diagnosed by a medical professional, and 289 (52.6%) not tested/diagnosed. Within the C+ cohort, 19.2% completed survey within 1-6 days of diagnosis, 51.2% within 1-4 weeks, 26.9% within 1-2 months, and 2.7% within 3-6 months.

Thus over 70% of respondents completed the survey within 1 month of diagnosis. 

Since onset of the COVID-19 pandemic, researchers sought to further our understanding of smell and taste changes associated with the disease. Initial work established acute loss of smell and taste as indicators of disease, with reported rates of chemosensory dysfunction among COVID-19 patients ranging from 30-85%. [8] [9] [10] Reported incidences reflect substantial variation due to differences in patient disease severity, timing of enrollment, study location, and assessment methods. Most studies determined degree of olfactory deficit as severe to complete anosmia in the majority of patients by self-report, 1, 9 or objective testing. 4 Despite this, early reports suggest rapid recovery. Our data suggest that within 1 month of diagnosis approximately J o u r n a l P r e -p r o o f 5 one third of patients recover to normal or near normal smell and taste. After an additional month, over two thirds had recovered to this level, while less than 5% reported their sense of smell or taste as absent.

Initial publications from Europe and Asia report higher rates of recovery. A French study of PCR-tested patients showed 98% experiencing a complete subjective recovery within 28 days, with mean duration of anosmia near 9 days. 11 Workers in the United Kingdom repeated surveys 1 week after initial survey, revealing that 80% had experienced some recovery, while only 17% remained anosmic. 12 They also noted a "plateau" in recovery after approximately 3 weeks, with a 70% recovery rate for those with anosmia of 3 or more weeks duration. Similarly, a study from Korea using daily phone surveys of almost 500 newly diagnosed COVID-19 patients showed median duration of anosmia or ageusia of 7 days, and almost all recovering within 3 weeks. 13 The current study has limitations which may account for these differences. These include selection and recall biases inherent in any survey. Additionally, over half of subjects were not COVID-19 tested, but presumed positive given high prevalence of infection, and reports showing markedly higher rates of smell loss in COVID-19 positive than negative patients. 10 

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