key: cord-0709282-04zbbyii
authors: Dawson, P.; Rabold, E. M.; Laws, R. L.; Conners, E. E.; Gharpure, R.; Yin, S.; Buono, S.; Dasu, T.; Bhattacharyya, S.; Westergaard, R. P.; Pray, I. W.; Ye, D.; Nabity, S. A.; Tate, J. E.; Kirking, H. L.
title: Loss of Taste and Smell as Distinguishing Symptoms of COVID-19
date: 2020-05-16
journal: nan
DOI: 10.1101/2020.05.13.20101006
sha: 75b3c5015f205edb21e98de6e69b5ed47b1a1515
doc_id: 709282
cord_uid: 04zbbyii

Olfactory and taste dysfunctions have emerged as symptoms of COVID-19. Among individuals with COVID-19 enrolled in a household study, loss of taste and/or smell was the fourth most commonly reported symptom (26/42; 62%), and among household contacts, it had the highest positive predictive value (83%; 95% CI: 55-95%) for COVID-19. These findings support consideration of loss of taste and/or smell in possible case identification and testing prioritization for COVID-19.

Among the 42 individuals with laboratory-confirmed SARS-CoV-2, all (100%) reported at least one symptom ( Table 1) ; 38 (90%) reported at least one classic COVID-19 symptom of fever, for use under a CC0 license. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20101006 doi: medRxiv preprint cough, or shortness of breath. The most frequently reported symptoms were cough (81%), headache (76%), fever (subjective or measured ≥ 100.4°F) (64%), loss of taste and/or smell (62%), nasal congestion (62%), myalgia (57%), and chills (55%).

Of the 26 participants with COVID-19 who reported loss of taste and/or smell, loss of taste was reported by 24 participants; 14/24 (58%) describing it as a complete loss. Loss of smell was reported by 18 participants; 13/18 (72%) describing it as a complete loss. There were no significant differences in reporting loss of taste and/or smell by sex, age <18 years versus 18 years or older, race/ethnicity, presence of preexisting medical conditions, or between index cases and household member cases (all p>0.05). Of the 26 participants reporting any loss of taste and/or smell, 9 (35%) reported it in the absence of nasal congestion, including 4 experiencing a complete loss of both taste and smell. Participants with COVID-19 reporting loss of taste and/or smell were more likely to report headache (88% vs. 56%; p=0.03) but were no more or less likely to report any other symptoms (p>0.05). No participant reported loss of taste and/or smell as the only symptom. Fifty-seven percent experienced loss of taste and/or smell along with at least one classic COVID-19 symptom, 55% with at least one other upper respiratory symptom (nasal congestion, sore throat, and rhinorrhea), and 62% with any other symptom. When loss of taste and/or smell was added to the classic symptoms, 95% of participants with COVID-19 reported at least one of loss of taste and/or smell, fever, cough, and shortness of breath.

Among the 64 household members of COVID-19 index cases, loss of taste and/or smell was reported by 12 individuals, of whom 10 were positive for SARS-CoV-2.

for use under a CC0 license. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20101006 doi: medRxiv preprint

The positive predictive value (PPV) of any loss of taste and/or smell for COVID-19 (83%, 95% CI: 55-95%) was higher than for fever (subjective or measured) and cough, two of the three classic symptoms, and equal to the third, shortness of breath (83%, 95% CI: 44-97%) ( Table 2) .

The PPV for complete loss of taste and/or smell (86%, 95% CI: 49-97%) was the highest among any of the symptoms.

In this household-based population of individuals with COVID-19, which included mildly symptomatic individuals who otherwise may not have been tested according to contemporaneous public health guidance, 7 loss of taste and/or smell was reported by more than three of every five individuals with confirmed COVID-19. Among the population of 64 household contacts of COVID-19 index cases, it had the highest positive predictive value for COVID-19 of all symptoms, only matched by shortness of breath. Prevalence of SARS-CoV-2 infection among household members of index cases was high, at 25%; therefore, PPV estimates may not be generalizable in populations with different background prevalence. However, our findings may be particularly relevant for screening individuals in close contact with known cases. When compared to most other symptoms, loss of taste and/or smell appeared highly predictive of SARS-CoV-2 infection and was more predictive than cough.

Nasal congestion alone is unlikely to explain the taste and smell alterations, as one-third of patients reporting loss of taste and/or smell did not report nasal congestion; other analyses have shown an even smaller proportion of COVID-19 cases with concurrent nasal congestion. 8

Proposed mechanisms for COVID-19-related olfactory and taste dysfunction include an affinity for coronaviruses to infect olfactory nerves in an animal model and the broad expression of the for use under a CC0 license.

This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20101006 doi: medRxiv preprint receptor involved in the pathogenesis of SARS-CoV-2 on the epithelial cells of the tongue and oral cavity mucosa. 6, 9, 10 With recent case series and case reports describing central and peripheral nervous system abnormalities, loss of taste and smell may represent only a subset of neurologic manifestations of COVID-19. 11, 12 This analysis is subject to limitations. All symptoms and medical histories were self-reported and limited by patient recall, health literacy (including younger children who may not have been able to adequately identify or describe symptoms), and availability of home thermometers. Symptoms prior to enrollment were collected retrospectively, and thus timelines for specific symptoms are not available. Because symptom ascertainment and SARS-CoV-2 testing were conducted at enrollment, any subsequent symptom development or detection of viral RNA that could affect PPVs for specific symptoms were not captured in this analysis. Prior reports have indicated that some symptoms, including the classic symptoms of fever and shortness of breath, may not present until later in the illness course. 13 Due to the high prevalence of COVID-19 infection within this population, the PPV identified in this analysis may not be representative of all clinical encounters. Finally, the sample size was small and was not powered for detecting differences among subpopulations, and resulted in wide overlapping confidence intervals for the reported PPVs.

In this investigation, adding loss of taste and/or smell to the classic clinical criteria would have captured 95% of cases while only misidentifying two non-cases as cases, compared to 14 noncases that would have been misidentified by the classic symptoms. CSTE recently added "new olfactory and taste disorder(s)" to its outpatient/telehealth clinical criteria for reporting. 4 In the for use under a CC0 license.

This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20101006 doi: medRxiv preprint absence of confirmatory laboratory testing, criteria for a probable COVID-19 case now include loss of taste and/or smell in conjunction with other non-classic symptoms. Our early findings from a household transmission investigation suggest that adding loss of taste and/or smell to the singular CSTE clinical criteria, which currently include cough, shortness of breath, and difficulty breathing, may increase the efficiency of probable COVID-19 case identification.

Due to limited testing capacity, most states have prioritized testing of moderately to severely ill patients. However, as the availability of contact tracing and testing expands, testing and diagnoses will shift to also include outpatients with milder illness. Identifying these cases will assist in appropriate isolation recommendations and the prevention of additional spread within the community. Clinicians will benefit from further characterization of the full spectrum of illness in patients and may consider using loss of taste and/or smell in their testing strategies. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05. 13.20101006 doi: medRxiv preprint The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 16, 2020. . https://doi.org/10.1101/2020.05.13.20101006 doi: medRxiv preprint

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