SynthesisThe Laryngoscope2021
Prevalence of Olfactory Dysfunction in Coronavirus Disease 2019 (COVID-19): A Meta-analysis of 27,492 Patients.
Synthesis in The Laryngoscope, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 120 papers, 9 of them syntheses that pooled it.
What it found
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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.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
120 citing papers in PubMed, 9 syntheses or guidelines pooled it, 209 citations in OpenAlex.
- Publication bias in otorhinolaryngology meta-analyses in 2021.Systematic reviews · 2024Pooled it
- Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis.Journal of neurology · 2023Pooled it
- Pooled it
- Pooled it
- Efficacy of topical steroids for the treatment of olfactory disorders caused by COVID-19: A systematic review and meta-analysis.Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery · 2022Pooled it
- [Guideline S1: Long COVID: Diagnostics and treatment strategies].Wiener klinische Wochenschrift · 2021Guideline
- Olfactory dysfunction amongst children and adolescents with laboratory confirmed coronavirus disease 2019: a systematic review.The Journal of laryngology and otology · 2021Pooled it
- Pooled it
- Pooled it
- Efficacy of forskolin as a promising therapy for chronic olfactory dysfunction post COVID-19.European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · 2024Trial
- Olfactory-Related Quality of Life After Endoscopic Transsphenoidal Surgery.Laryngoscope investigative otolaryngology · 2026Article
- Olfactory Training for COVID-19-Related Olfactory Dysfunction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.Turkish archives of otorhinolaryngology · 2026Article
- A Cross-Sectional Study Exploring Patient Experiences, Unmet Needs and Desired Support in Those With Olfactory Dysfunction.Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery · 2026Article
- Genome-wide DNA methylation profiling in COVID-19 positive patients reveals alterations in pathways linked to neurological dysfunction.Clinical epigenetics · 2026Article
- Review
- SARS-CoV-2 pseudoparticles preferentially infect ectoderm in human embryonic tissues.Frontiers in cell and developmental biology · 2026Article
- Improved Nasal Airflow Is Associated With Olfactory Recovery in a Large Population of Patients With COVID-19-Related Olfactory Dysfunction.Laryngoscope investigative otolaryngology · 2025Article
- Olfactory Training for Post-COVID-19 Olfactory Dysfunction: A Meta-Analysis of Efficacy and Combination Therapies.Journal of clinical medicine · 2025Review
- 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
- Unmasking Risk Factors for Post-COVID-19 Olfactory Dysfunction Resulting From Early Stages of the Pandemic: A Case-Control Study of Lost and Lingering Smells.The Permanente journal · 2025Article
60 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectives/hypothesisOlfactory dysfunction has been observed as one of the clinical manifestations in COVID-19 patients. We aimed to conduct a systematic review and meta-analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID-19 patients. STUDY
designSystematic review and meta-analyses.
methodsPubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random-effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I
resultsWe identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta-analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID-19 patients was 47.85% [95% CI: 41.20-54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID-19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false-negative reporting observed in self-reported health measures.
conclusionsThe prevalence of olfactory dysfunction in COVID-19 patients was found to be 47.85% based on high-quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding. LEVEL OF EVIDENCE: 2 Laryngoscope, 131:865-878, 2021.
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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.