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The Centre for Evidence-Based Medicine (CEBM) at Oxford University develops, promotes and disseminates better evidence for health care.
ACCORD guideline for reporting consensus-based methods in biomedical research and clinical practice: a study protocol.
BACKGROUND: Structured, systematic methods to formulate consensus recommendations, such as the Delphi process or nominal group technique, among others, provide the opportunity to harness the knowledge of experts to support clinical decision making in areas of uncertainty. They are widely used in biomedical research, in particular where disease characteristics or resource limitations mean that high-quality evidence generation is difficult. However, poor reporting of methods used to reach a consensus - for example, not clearly explaining the definition of consensus, or not stating how consensus group panellists were selected - can potentially undermine confidence in this type of research and hinder reproducibility. Our objective is therefore to systematically develop a reporting guideline to help the biomedical research and clinical practice community describe the methods or techniques used to reach consensus in a complete, transparent, and consistent manner. METHODS: The ACCORD (ACcurate COnsensus Reporting Document) project will take place in five stages and follow the EQUATOR Network guidance for the development of reporting guidelines. In Stage 1, a multidisciplinary Steering Committee has been established to lead and coordinate the guideline development process. In Stage 2, a systematic literature review will identify evidence on the quality of the reporting of consensus methodology, to obtain potential items for a reporting checklist. In Stage 3, Delphi methodology will be used to reach consensus regarding the checklist items, first among the Steering Committee, and then among a broader Delphi panel comprising participants with a range of expertise, including patient representatives. In Stage 4, the reporting guideline will be finalised in a consensus meeting, along with the production of an Explanation and Elaboration (E&E) document. In Stage 5, we plan to publish the reporting guideline and E&E document in open-access journals, supported by presentations at appropriate events. Dissemination of the reporting guideline, including a website linked to social media channels, is crucial for the document to be implemented in practice. DISCUSSION: The ACCORD reporting guideline will provide a set of minimum items that should be reported about methods used to achieve consensus, including approaches ranging from simple unstructured opinion gatherings to highly structured processes.
Background: Modes of transmission of SARS-CoV-2 are of key public health importance. SARS-CoV-2 has been detected in the feces of some COVID-19 patients, suggesting the possibility that the virus could, in addition to droplet and fomite transmission, be transmitted via the orofecal route. Methods: This review is part of an Open Evidence Review on Transmission Dynamics of COVID-19. We conduct ongoing searches using WHO COVID-19 Database, LitCovid, medRxiv, and Google Scholarassess study quality based on five criteria and report important findings. Where necessary, authors are contacted for further details on the content of their articles. Results: We include searches up until 20 December 2020. We included 110 relevant studies: 76 primary observational studies or reports, and 35 reviews (one cohort study also included a review) examining the potential role of orofecal transmission of SARS-CoV-2. Of the observational studies, 37 were done in China. A total of 48 studies (n=9,081 patients) reported single cases, case series or cohort data on individuals with COVID-19 diagnosis or their contacts and 46 (96%) detected binary RT-PCR with 535 out of 1358 samples positive for SARS-CoV-2 (average 39.4%). The results suggest a long duration of fecal shedding, often recorded after respiratory samples tested negative, and symptoms of gastrointestinal disease were reported in several studies. Twenty-nine studies reported finding SARS-CoV-2 RNA in wastewater, river water or toilet areas. Six studies attempted viral culture from COVID-19 patients' fecal samples: culture was successful in 3 of 6 studies, and one study demonstrated invasion of the virus into intestinal epithelial cells. Conclusions: Varied observational and mechanistic evidence suggests SARS-CoV-2 can infect and be shed from the gastrointestinal tract, including some data demonstrating viral culture in fecal samples. To fully assess these risks, quantitative data on infectious virus in these settings and infectious dose are needed.
Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) from pre and asymptomatic infected individuals: a systematic review
Background: The role of SARS-Cov-2-infected persons who develop symptoms after testing (presymptomatics) or not at all (asymptomatics) in the pandemic spread is unknown. Objectives: To determine infectiousness and probable contribution of asymptomatic persons (at the time of testing) to pandemic SARS-CoV-2 spread. Data sources: LitCovid, medRxiv, Google Scholar, and WHO Covid-19 databases (to 31 March 2021) and references in included studies. Study eligibility criteria: Studies with a proven or hypothesized transmission chain based either on serial PCR cycle threshold readings and/or viral culture and/or gene sequencing, with adequate follow-up. Participants: People exposed to SARS-CoV-2 within 2–14 days to index asymptomatic (at time of observation) infected individuals. Interventions: Reliability of symptom and signs was assessed within contemporary knowledge; transmission likelihood was assessed using adapted causality criteria. Methods: Systematic review. We contacted all included studies' corresponding authors requesting further details. Results: We included 18 studies from a diverse setting with substantial methodological variation (this field lacks standardized methodology). At initial testing, prevalence of asymptomatic cases was 12.5–100%. Of these, 6–100% were later determined to be presymptomatic, this proportion varying according to setting, methods of case ascertainment and population. Nursing/care home facilities reported high rates of presymptomatic: 50–100% (n = 3 studies). Fourteen studies were classified as high risk of, and four studies as at moderate risk of symptom ascertainment bias. High-risk studies may be less likely to distinguish between presymptomatic and asymptomatic cases. Six asymptomatic studies and four presymptomatic studies reported culturing infectious virus; data were too sparse to determine infectiousness duration. Three studies provided evidence of possible and three of probable/likely asymptomatic transmission; five studies provided possible and two probable/likely presymptomatic SARS-CoV-2 transmission. Conclusion: High-quality studies provide probable evidence of SARS-CoV-2 transmission from presymptomatic and asymptomatic individuals, with highly variable estimated transmission rates.
RATIONALE FOR THE REVIEW: Air travel may be associated with viruses spread via infected passengers and potentially through in-flight transmission. Given the novelty of the Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, transmission associated with air travel is based on transmission dynamics of other respiratory viruses. Our objective was to provide a rapid summary and evaluation of relevant data on SARS-CoV-2 transmission aboard aircraft, report policy implications and to highlight research gaps requiring urgent attention. METHODS: We searched four electronic databases (1 February 2020-27 January 2021) and included studies on SARS-CoV-2 transmission aboard aircraft. We assessed study quality based on five criteria and reported important findings. KEY FINDINGS: We included 18 studies on in-flight SARS-CoV-2 transmission (130 unique flights) and 2 studies on wastewater from aircraft. The quality of evidence from most published studies was low. Two wastewater studies reported PCR-positive samples with high cycle threshold values (33-39). Index case definition was heterogeneous across studies. The proportion of contacts traced ranged from 0.68 to 100%. Authors traced 2800/19 729 passengers, 140/180 crew members and 8/8 medical staff. Altogether, 273 index cases were reported, with 64 secondary cases. Three studies, each investigating one flight, reported no secondary cases. Secondary attack rate among studies following up >80% of passengers and crew (including data on 10 flights) varied between 0 and 8.2%. The studies reported on the possibility of SARS-CoV-2 transmission from asymptomatic, pre-symptomatic and symptomatic individuals. Two studies performed viral cultures with 10 positive results. Genomic sequencing and phylogenetic analysis were performed in individuals from four flights. CONCLUSION: Current evidence suggests SARS-CoV-2 can be transmitted during aircraft travel, but published data do not permit any conclusive assessment of likelihood and extent. The variation in design and methodology restricts the comparison of findings across studies. Standardized guidelines for conducting and reporting future studies of transmission on aircraft should be developed.
Background: Airborne transmission is the spread of an infectious agent caused by the dissemination of droplet nuclei (aerosols) that remain infectious when suspended in the air. We carried out a systematic review to identify, appraise and summarise the evidence from studies of the role of airborne transmission of SARS-CoV-2. Methods: : We searched LitCovid, MedRxiv, Google Scholar and the WHO Covid-19 database from 1 February to 20 December 2020 and included studies on airborne transmission. Data were dual extracted and we assessed quality using a modified QUADAS 2 risk of bias tool. Results: : We included 67 primary studies and 22 reviews on airborne SARS-CoV-2. Of the 67 primary studies, 53 (79%) reported data on RT-PCR from air samples, 12 (18%) report cycle threshold values and 18 (127%) copies per sample volume. All primary studies were observational and of low quality. The research often lacked standard methods, standard sampling sizes and reporting items. We found 36 descriptions of different air samplers deployed. Of the 42 studies conducted in-hospital that reported binary RT-PCR tests, 24 (57%) reported positive results for SARs-CoV-2 (142 positives out of 1,403 samples: average 10.1%, range 0% to 100%). There was no pattern between the type of hospital setting (ICU versus non-ICU) and RT-PCR positivity. Seventeen studies reported potential air transmission in the outdoors or in the community, of which seven performed RT-PCR sampling, and two studies reported weak positive RNA samples for 2 or more genes (5 of 125 samples positive: average 4.0%). Ten studies attempted viral culture with no serial passage. Conclusion: SARS-CoV-2 RNA is detected intermittently in the air in various settings. Standardized guidelines for conducting and reporting research on airborne transmission are needed. The lack of recoverable viral culture samples of SARS-CoV-2 prevents firm conclusions from being drawn about airborne transmission.
Background: SARS-CoV-2 transmission has been reported to be associated with close contact with infected individuals. However, the mechanistic pathway for transmission in close contact settings is unclear. Our objective was to identify, appraise and summarise the evidence from studies assessing the role of close contact in SARS-CoV-2 transmission. Methods: : This review is part of an Open Evidence Review on Transmission Dynamics of SARS-CoV-2. We conduct ongoing searches using WHO Covid-19 Database, LitCovid, medRxiv, PubMed and Google Scholar; assess study quality based on the QUADAS-2 criteria and report important findings on an ongoing basis. Results: : We included 181 studies: 171 primary studies and 10 systematic reviews. The settings for primary studies were predominantly in home/quarantine facilities (31.6%) and acute care hospitals (15.2%). The overall reporting quality of the studies was low to moderate. There was significant heterogeneity in design and methodology. The frequency of attack rates (PCR testing) was 3.5-75%; attack rates were highest in prison and wedding venues, and in households. The frequency of secondary attack rates was 0.3-100% with rates highest in home/quarantine settings. Three studies showed no transmission if index cases had recurrent infection. Viral culture was performed in three studies of which two found viable virus; culture results were negative where index cases had recurrent infections. Ten studies performed genomic sequencing with phylogenetic analysis – the completeness of genomic similarity ranged from 81-100%. Findings from systematic reviews showed that children were significantly less likely to transmit SARS-CoV-2 and household contact was associated with a significantly increased risk of infection. Conclusions: : The evidence from published studies demonstrates that SARS-CoV-2 can be transmitted via close contact settings. The risk of transmission is greater in household contacts. There was wide variation in methodology. Standardized guidelines for reporting transmission in close contact settings should be developed to improve the quality reporting.
© 2020 John Wiley & Sons Ltd Background and aims: Liver cirrhosis severely decreases patients' quality of life. Since self-management programmes have improved quality of life and reduce hospital admissions in other chronic diseases, they have been suggested to decrease liver cirrhosis burden. Methods: We performed a systematic review and meta-analysis to evaluate the clinical impact of self-management programmes in patients with liver cirrhosis, which followed the Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Primary outcomes include health-related quality of life (HRQOL) and hospitalisation. We searched MEDLINE, CENTRAL, Embase, CINAHL, PsycINFO and two trial registers to July 2017. Results: We identified four randomised trials (299 patients) all rated at a high risk of bias. No difference was demonstrated for HRQOL (standardised mean difference −0.01, 95% CI: −0.48 to 0.46) and hospitalisation days (incidence rate ratio 1.6, 95% CI: 0.5–4.8). For secondary outcomes, one study found a statistically significant improvement in patient knowledge (mean difference (MD) 3.68, 95% CI: 2.11–5.25) while another study found an increase in model for end-stage liver disease scores (MD 2.8, 95% CI: 0.6–4.9) in the self-management group. No statistical difference was found for the other secondary outcomes (self-efficacy, psychological health outcomes, healthcare utilisation, mortality). Overall, the quality of the evidence was low. The content of self-management programmes varied across studies with little overlap. Conclusions: The current literature indicates that there is no evidence of a benefit of self-management programmes for people with cirrhosis. Relevance to clinical practice: Practitioners should use self-management programmes with caution when delivering care to patients living with cirrhosis. Further research is required to determine what are the key features in a complex intervention like self-management. This review offers a preliminary framework for clinicians to develop a new self-management programme with key features of effective self-management interventions from established models.
© 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. The cells of the mononuclear phagocyte system (MPS) constitute a dispersed organ, which is distributed throughout the body. Macrophages in different tissues display distinctive mosaic phenotypes as resident and recruited cells of embryonic and bone marrow origin, respectively. They help to maintain homeostasis during development and throughout adult life, yet contribute to the pathogenesis of many disease processes, including inflammation, innate and adaptive immunity, metabolic disorders, and cancer. Heterogeneous tissue macrophage populations display a wide variety of surface molecules to recognise and respond to host, microbial, and exogenous ligands in their environment; their receptors mediate the uptake and destruction of effete and dying host cells and pathogens, as well as contribute trophic and secretory functions within every organ in the body. Apart from local cellular interactions, macrophage surface molecules and products serve to mobilise and coordinate systemic humoral and cellular responses. Their use as antigen markers in pathogenesis and as potential drug targets has lagged in clinical pathology and human immunotherapy. In this review, we summarise the properties of selected surface molecules expressed on macrophages in different tissues and disease processes, to provide a functional basis for diagnosis, further research, and treatment. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.