SynthesisPloS one2021
Olfactory recovery following infection with COVID-19: A systematic review.
Synthesis in PloS one, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04789499 (Smell in Covid-19 and Efficacy of Nasal Theophylline), which is not on this map. Cited by 25 papers, 1 of them a synthesis 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.
Smell in Covid-19 and Efficacy of Nasal Theophylline
Who cites it
25 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- Efficacy and Safety of Saline Nasal Irrigation Plus Theophylline for Treatment of COVID-19-Related Olfactory Dysfunction: The SCENT2 Phase 2 Randomized Clinical Trial.JAMA otolaryngology-- head & neck surgery · 2022Trial
- Lost and Found: Is Olfactory Recovery More Promising After COVID-19 Than Other Causes, Even 2 Years Later?International forum of allergy & rhinology · 2026Article
- Presentation and temporal nature of postacute sequelae of SARS-CoV-2 infection in a US national cohort.Brain, behavior, & immunity - health · 2026Article
- Prevalence and Clinical Factors Associated with Self-reported Smell and Taste Disorders in Older Adults Hospitalized with COVID-19.International archives of otorhinolaryngology · 2025Article
- Olfactory Dysfunction and Limbic Hypoactivation in Temporal Lobe Epilepsy.Human brain mapping · 2024Article
- Impact of post-COVID-19 olfactory disorders on quality of life, hedonic experiences and psychiatric dimensions in general population.BMC psychiatry · 2024Article
- Long COVID: neurological manifestations - an updated narrative review.Dementia & neuropsychologia · 2024Review
- Clinical factors influencing olfactory performance in patients with persistent COVID-19 smell loss longer than 1 year.Laryngoscope investigative otolaryngology · 2023Article
- Considerations in Children and Adolescents Related to Coronavirus Disease 2019 (COVID-19).Physical medicine and rehabilitation clinics of North America · 2023Review
- Physical and cognitive impact following SARS-CoV-2 infection in a large population-based case-control study.Communications medicine · 2023Article
- Evaluation of Clinical Features and Olfactory Functions in COVID-19: A Multicentre Study.Cureus · 2023Article
- Article
- Article
- Smell Outcome and Seropositivity Titre in Post-COVID-19 Patients.ORL; journal for oto-rhino-laryngology and its related specialties · 2023Article
- A multicenter real-life study to determine the efficacy of corticosteroids and olfactory training in improving persistent COVID-19-related olfactory dysfunction.Laryngoscope investigative otolaryngology · 2022Article
- Sociodemographic Characteristics and Comorbidities of Patients With Long COVID and Persistent Olfactory Dysfunction.JAMA network open · 2022Article
- Olfactory dysfunction in COVID-19: pathology and long-term implications for brain health.Trends in molecular medicine · 2022Review
- Analysis of Prevalence and Predictive Factors of Long-Lasting Olfactory and Gustatory Dysfunction in COVID-19 Patients.Life (Basel, Switzerland) · 2022Article
- Olfactory Training in Post-COVID-19 Persistent Olfactory Disorders: Value Normalization for Threshold but Not Identification.Journal of clinical medicine · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Olfactory loss has been identified as one of the common symptoms related to COVID-19 infection. Although olfactory loss is recognized, our understanding of both the extent of loss and time to olfactory recovery following infection is less well known. Similarly, knowledge of potential impactful patient factors and therapies that influence olfactory recovery is desirable but is not overtly clear in the literature. Our systematic review sought to fill this knowledge gap. We included studies that: involved either an observational or an interventional design that reported data on patients with olfactory dysfunction due to Reverse Transcription Polymerase Chain Reaction (RT-PCR) diagnosed COVID-19 infection; and reported data regarding olfactory recovery measured by an objective olfactory test, Likert scale and/or visual analog scale (VAS). The study methods were determined a priori and registered in PROSPERO (Registration Number CRD42020204354). An information specialist searched Medline, Embase, LitCovid and the Cochrane Register of Controlled Trials up to March 2021, and two reviewers were involved in all aspects of study selection and data collection. After screening 2788 citations, a total of 44 studies of assorted observational designs were included. Patients had undergone objective COVID-19 testing, and most were adult patients with mild to moderate COVID-19. Olfactory recovery was found to occur as early as 7 days, with most patients recovering olfaction within 30 days. Few studies included prolonged follow-up to 6 months or longer duration. Poor olfaction at initial presentation was associated with poor recovery rates. Only a small number of studies assessed olfactory retraining and steroid therapy. Additional trials are underway.
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.