SynthesisChemical senses2020
Objective Sensory Testing Methods Reveal a Higher Prevalence of Olfactory Loss in COVID-19-Positive Patients Compared to Subjective Methods: A Systematic Review and Meta-Analysis.
Synthesis in Chemical senses, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 120 papers, 10 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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, 10 syntheses or guidelines pooled it.
- Efficacy of Omega-3 supplementation in olfactory dysfunction: a systematic review of randomized controlled trials.BMC nutrition · 2025Pooled it
- Treatment of COVID-19 Associated Olfactory Dysfunction: A Systematic Review.Current allergy and asthma reports · 2024Pooled it
- A systematic review of the biological mediators of fat taste and smell.Physiological reviews · 2023Pooled it
- Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis.Chemical senses · 2023Pooled it
- Qualitative Olfactory Dysfunction and COVID-19: An Evidence-Based Review with Recommendations for the Clinician.American journal of rhinology & allergy · 2023Pooled it
- Association of Olfactory Impairment With All-Cause Mortality: A Systematic Review and Meta-analysis.JAMA otolaryngology-- head & neck surgery · 2022Pooled it
- Treatment strategies for postviral olfactory dysfunction: A systematic review.Allergy and asthma proceedings · 2022Pooled it
- The D614G Virus Mutation Enhances Anosmia in COVID-19 Patients: Evidence from a Systematic Review and Meta-analysis of Studies from South Asia.ACS chemical neuroscience · 2021Pooled it
- Is loss of smell an early predictor of COVID-19 severity: a systematic review and meta-analysis.Archives of pharmacal research · 2021Pooled it
- Prevalence of Chemosensory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis Reveals Significant Ethnic Differences.ACS chemical neuroscience · 2020Pooled it
- Limited observed efficacy of olfactory training in severe long-term post-COVID-19 syndrome: a prospective cohort study.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 · 2026Article
- A new framework for the labeling of odors in the Sniffin' Sticks odor identification test: relevance of familiarity and test-retest assessment.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 · 2026Article
- Association between Objective and Subjective Olfactory Dysfunction in SARS-CoV-2-Positive Patients Undergoing Skull Base Surgery.Journal of neurological surgery. Part B, Skull base · 2026Article
- "I Can Taste It, But Sometimes It's Disgusting" Cross-sectional Study on the Influence of SARS-CoV-2 Infections, Both Acute and Postinfection, in Comparison to Other Respiratory Infections on Taste and Smell Perception.The Pediatric infectious disease journal · 2026Article
- Life satisfaction among cancer survivors with and without smell and taste dysfunction: evidence from the National Health Interview Survey.Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2026Article
- Transcriptional regulation of the main olfactory epithelium by environmental olfactory exposures.bioRxiv : the preprint server for biology · 2026Article
- Life Satisfaction Among Cancer Survivors With and Without Smell and Taste Dysfunction: Evidence from the National Health Interview Survey.medRxiv : the preprint server for health sciences · 2025Article
- Clinical Application and Limitations of a Digitalized Olfactory Function Test Including Threshold, Discrimination, and Identification Subsets.Clinical and experimental otorhinolaryngology · 2025Article
- Olfactory Dysfunction After SARS-CoV-2 Infection in the RECOVER Adult Cohort.JAMA network open · 2025Article
- Sensing Sociality: Disruptions of Social Life When Living With Chemosensory Dysfunctions After COVID-19.Qualitative health research · 2025Article
60 more citing papers are in PubMed but not listed here.
Corrections and comments
- Update of
Authors and funding
8 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide. In response to the pandemic, numerous studies have tried to identify the causes and symptoms of the disease. Emerging evidence supports recently acquired anosmia (complete loss of smell) and hyposmia (partial loss of smell) as symptoms of COVID-19, but studies of olfactory dysfunction show a wide range of prevalence from 5% to 98%. We undertook a search of Pubmed/Medline and Google Scholar with the keywords "COVID-19," "smell," and/or "olfaction." We included any study that quantified smell loss (anosmia and hyposmia) as a symptom of COVID-19. Studies were grouped and compared based on the type of method used to measure smell loss-subjective measures, such as self-reported smell loss, versus objective measures using rated stimuli-to determine if prevalence differed by method type. For each study, 95% confidence intervals (CIs) were calculated from point estimates of olfactory disturbances. We identified 34 articles quantifying anosmia as a symptom of COVID-19 (6 objective and 28 subjective), collected from cases identified from January 16 to April 30, 2020. The pooled prevalence estimate of smell loss was 77% when assessed through objective measurements (95% CI of 61.4-89.2%) and 44% with subjective measurements (95% CI of 32.2-57.0%). Objective measures are a more sensitive method to identify smell loss as a result of infection with SARS-CoV-2; the use of subjective measures, while expedient during the early stages of the pandemic, underestimates the true prevalence of smell loss.
Indexed as
Identifiers
What OpenQuestion holds
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.