ArticleChemical senses2021
Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms.
Article in Chemical senses, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 111 papers, 6 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
111 citing papers in PubMed, 6 syntheses or guidelines pooled it, 181 citations in OpenAlex.
- Topographical Distribution of Neuroanatomical Abnormalities Following COVID-19 Invasion : A Systematic Literature Review.Clinical neuroradiology · 2024Pooled it
- Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis.Chemical senses · 2023Pooled it
- Interventions for the prevention of persistent post-COVID-19 olfactory dysfunction.The Cochrane database of systematic reviews · 2022Pooled it
- Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19.The Cochrane database of systematic reviews · 2022Pooled it
- Treatment strategies for postviral olfactory dysfunction: A systematic review.Allergy and asthma proceedings · 2022Pooled it
- Interventions for the prevention of persistent post-COVID-19 olfactory dysfunction.The Cochrane database of systematic reviews · 2021Pooled it
- Self-reported symptom study of COVID-19 chemosensory dysfunction in Malaysia.Scientific reports · 2022Trial
- Ultramicronized Palmitoylethanolamide and Luteolin Supplement Combined with Olfactory Training to Treat Post-COVID-19 Olfactory Impairment: A Multi-Center Double-Blinded Randomized Placebo- Controlled Clinical Trial.Current neuropharmacology · 2022Trial
- Presentation and temporal nature of postacute sequelae of SARS-CoV-2 infection in a US national cohort.Brain, behavior, & immunity - health · 2026Article
- Quality of Life and Chemosensory Function in Post-COVID Patients: Adherence to Olfactory Training.The Annals of otology, rhinology, and laryngology · 2026Article
- Evaluating methods for quantitative olfactory assessment: a comparative longitudinal analysis of Sniffin' Sticks and alternative tools.Chemical senses · 2026Article
- Objective assessment of long-term impact of COVID-19 on multiple sensory functions.BMC medicine · 2026Article
- Sudden sensorineural olfactory loss: a structured narrative review and proposal for a standardised terminological framework.Frontiers in surgery · 2026Review
- Subjective smell- and taste loss in diabetes-A questionnaire-based study on 47 011 individuals with diabetes and matched controls.Diabetes, obesity & metabolism · 2025Article
- Self-Reported Parosmia, Phantosmia, and Gustatory Dysfunction Among Adults with Mild-to-Moderate COVID-19: A Cross-Sectional Study in Saudi Arabia.Clinics and practice · 2025Article
- Effects of one year of extreme isolation in Antarctica on olfactory and gustatory functions.Scientific reports · 2025Article
- Sensing Sociality: Disruptions of Social Life When Living With Chemosensory Dysfunctions After COVID-19.Qualitative health research · 2025Article
- Article
- Sensory effects of COVID-19 in wine professionals.PloS one · 2025Article
- The potential of olfaction loss to induce cognitive impairment and anxiety behavior in mice via the microbiota-gut-brain axis.Frontiers in microbiology · 2025Article
51 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
72 authors at 20 institutions in 33 countries.
Funding
Abstract
In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19-; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19- groups exhibited smell loss, but it was significantly larger in C19+ participants (mean ± SD, C19+: -82.5 ± 27.2 points; C19-: -59.8 ± 37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC = 0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0-10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4 < OR < 10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.