Impairments in odour detection and hedonic ratings of unpleasant smells in asymptomatic university students as SARS‐Cov‐2 emerged locally

  1. Julie Walsh‐Messinger
  2. Sahar Kaouk
  3. Hannah Manis
  4. Rachel Kaye
  5. Guillermo Cecchi
  6. Pablo Meyer
  7. Dolores Malaspina

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Abstract

Sudden olfactory loss in the absence of concurrent nasal congestion is now a well‐recognized symptom of COVID‐19. We examined olfaction using standardized objective tests of odour detection, identification and hedonics collected from asymptomatic university students before and as SARS‐CoV‐2 emerged locally. Olfactory performance of students who were tested when the virus is known to be endemic ( n  = 22) was compared to students tested in the month prior to viral circulation ( n  = 25), a normative sample assessed during the previous 4 years ( n  = 272) and those tested in prior years during the same time period. Analyses showed significantly reduced odour detection for the virus exposed cohort compared to students tested before ( t  = 2.60; P  = .01; d  = 0.77; CI 0.17, 1.36) and to the normative sample ( D  = 0.38; P  = .005). Odour identification scores were similar, but the exposed cohort rated odours as less unpleasant ( P  < .001, CLES = 0.77). Hyposmia increased 4.4‐fold for students tested 2 weeks before school closure ( N  = 22) and increased 13.6‐fold for students tested in the final week ( N  = 11). While the unavailability of COVID‐19 testing is a limitation, this naturalistic study demonstrates week‐by‐week increase in hyposmia in asymptomatic students as a virus was circulating on campus, consistent with increasing airborne viral loads. The specific hedonic deficit in unpleasantness appraisal suggests a deficit in the TAAR olfactory receptor class, which conveys the social salience of odours. Assessment of odour detection and hedonic ratings may aid in early detection of SARS‐CoV‐2 exposure in asymptomatic and pre‐symptomatic persons.

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  1. Version published to 10.1111/ejn.15430
  2. Version published to 10.1101/2020.06.17.20106302v3 on medRxiv
  3. Version published to 10.1101/2020.06.17.20106302v2 on medRxiv
  4. ScreenIT

    SciScore for 10.1101/2020.06.17.20106302: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    This research will never be replicated; yet it is not without limitations. The sample sizes of the 2020 cohorts are small, although we still found moderate to large effects and statistical significance. Further, given the few cases of SARS-CoV-2 now known locally at the time Cohort I was tested, it is possible that some Cohort I participants could also have been exposed to the virus prior to testing; we do know that students tested from 2016–2019 were not exposed to the novel virus. Although our subjects were healthy and without nasal symptoms, we did not explicitly assess COVID-19 symptoms at the time of olfaction testing as the studies were not designed to test hypotheses related to infectious diseases. The absence of SARS-CoV-2 positivity confirmation also limits our ability to definitively draw the conclusion about exposure to SARS-CoV-2 at the time Cohort II participated. The retrospective nature of our health survey and lack of local and national access to COVID-19 testing for young adults also limits our health survey results. The State of Ohio, where at almost half of the students reside, only allowed access to COVID-19 testing for non-high-risk persons <60 and non-healthcare workers on June 11, 2020 [36]. Conclusions: This report adds a scientifically rigorous perspective to the early clinician and patient reports associating anosmia/hyposmia and ageusia/dysgeusia with COVID-19 [37-40], which propelled the American Academy of Otolaryngology to advocate for the CDC an...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  5. Version published to 10.1101/2020.06.17.20106302v1 on medRxiv