ObjectiveTo compare the effects of treatments for coronavirus disease 2019 (covid-19).DesignLiving systematic review and network meta-analysis.Data sourcesUS Centers for Disease Control and Prevention COVID-19 Research Articles Downloadable Database, which includes 25 electronic databases and six additional Chinese databases to 20 July 2020.Study selectionRandomised clinical trials in which people with suspected, probable, or confirmed covid-19 were randomised to drug treatment or to standard care or placebo. Pairs of reviewers independently screened potentially eligible articles.MethodsAfter duplicate data abstraction, a bayesian random effects network meta-analysis was conducted. Risk of bias of the included studies was assessed using a modification of the Cochrane risk of bias 2.0 tool, and the certainty of the evidence using the grading of recommendations assessment, development and evaluation (GRADE) approach. For each outcome, interventions were classified in groups from the most to the least beneficial or harmful following GRADE guidance.Results23 randomised controlled trials were included in the analysis performed on 26 June 2020. The certainty of the evidence for most comparisons was very low because of risk of bias (lack of blinding) and serious imprecision. Glucocorticoids were the only intervention with evidence for a reduction in death compared with standard care (risk difference 37 fewer per 1000 patients, 95% credible interval 63 fewer to 11 fewer, moderate certainty) and mechanical ventilation (31 fewer per 1000 patients, 47 fewer to 9 fewer, moderate certainty). These estimates are based on direct evidence; network estimates for glucocorticoids compared with standard care were less precise because of network heterogeneity. Three drugs might reduce symptom duration compared with standard care: hydroxychloroquine (mean difference −4.5 days, low certainty), remdesivir (−2.6 days, moderate certainty), and lopinavir-ritonavir (−1.2 days, low certainty). Hydroxychloroquine might increase the risk of adverse events compared with the other interventions, and remdesivir probably does not substantially increase the risk of adverse effects leading to drug discontinuation. No other interventions included enough patients to meaningfully interpret adverse effects leading to drug discontinuation.ConclusionGlucocorticoids probably reduce mortality and mechanical ventilation in patients with covid-19 compared with standard care. The effectiveness of most interventions is uncertain because most of the randomised controlled trials so far have been small and have important study limitations.Systematic review registrationThis review was not registered. The protocol is included as a supplement.Readers’ noteThis article is a living systematic review that will be updated to reflect emerging evidence. Updates may occur for up to two years from the date of original publication.

Clinical questionWhat is the role of drug interventions in the treatment and prevention of covid-19?RecommendationsThe first version on this living guidance focuses on corticosteroids. It contains a strong recommendation for systemic corticosteroids in patients with severe and critical covid-19, and a weak or conditional recommendation against systemic corticosteroids in patients with non-severe covid-19. Corticosteroids are inexpensive and are on the World Health Organisation list of essential medicines.Howthis guideline was created This guideline reflects an innovative collaboration between the WHO and the MAGIC Evidence Ecosystem Foundation, driven by an urgent need for global collaboration to provide trustworthy and living covid-19 guidance. A standing international panel of content experts, patients, clinicians, and methodologists, free from relevant conflicts of interest, produce recommendations for clinical practice. The panel follows standards, methods, processes, and platforms for trustworthy guideline development using the GRADE approach. We apply an individual patient perspective while considering contextual factors (that is, resources, feasibility, acceptability, equity) for countries and healthcare systems.The evidenceA living systematic review and network meta-analysis, supported by a prospective meta-analysis, with data from eight randomised trials (7184 participants) found that systemic corticosteroids probably reduce 28 day mortality in patients with critical covid-19 (moderate certainty evidence; 87 fewer deaths per 1000 patients (95% confidence interval 124 fewer to 41 fewer)), and also in those with severe disease (moderate certainty evidence; 67 fewer deaths per 1000 patients (100 fewer to 27 fewer)). In contrast, systemic corticosteroids may increase the risk of death in patients without severe covid-19 (low certainty evidence; absolute effect estimate 39 more per 1000 patients, (12 fewer to 107 more)). Systemic corticosteroids probably reduce the need for invasive mechanical ventilation, and harms are likely to be minor (indirect evidence).Understanding the recommendationsThe panel made a strong recommendation for use of corticosteroids in severe and critical covid-19 because there is a lower risk of death among people treated with systemic corticosteroids (moderate certainty evidence), and they believe that all or almost all fully informed patients with severe and critical covid-19 would choose this treatment. In contrast, the panel concluded that patients with non-severe covid-19 would decline this treatment because they would be unlikely to benefit and may be harmed. Moreover, taking both a public health and a patient perspective, the panel warned that indiscriminate use of any therapy for covid-19 would potentially rapidly deplete global resources and deprive patients who may benefit from it most as potentially lifesaving therapy.UpdatesThis is a living guideline. Work is under way to evaluate other interventions. New recommendations will be published as updates to this guideline.Readers noteThis is version 1 of the living guideline, published on 4 September (BMJ 2020;370:m3379) version 1. Updates will be labelled as version 2, 3 etc. When citing this article, please cite the version number.SubmittedAugust 28AcceptedAugust 31

Background: Respiratory protective devices are critical in protecting against infection in healthcare workers at high risk of novel 2019 coronavirus disease (COVID-19); however, recommendations are conflicting and epidemiological data on their relative effectiveness against COVID-19 are limited. Purpose: To compare medical masks to N95 respirators in preventing laboratoryconfirmed viral infection and respiratory illness including coronavirus specifically in healthcare workers. Study Selection: Randomized controlled trials (RCTs) comparing the protective effect of medical masks to N95 respirators in healthcare workers. Data Extraction: Reviewer pair independently screened, extracted data, and assessed risk of bias and the certainty of the evidence.Data Synthesis: Four RCTs were meta-analyzed adjusting for clustering. Compared with N95 respirators; the use of medical masks did not increase laboratory-confirmed viral (including coronaviruses) respiratory infection (OR 1.06; 95% CI 0.90-1.25; I 2 = 0%; low certainty in the evidence) or clinical respiratory illness (OR 1.49; 95% CI: 0.98-2.28; I 2 = 78%; very low certainty in the evidence). Only one trial evaluated coronaviruses separately and found no difference between the two groups (P = .49). Limitations: Indirectness and imprecision of available evidence.Conclusions: Low certainty evidence suggests that medical masks and N95 respirators offer similar protection against viral respiratory infection including coronavirus in healthcare workers during non-aerosol-generating care. Preservation of N95 S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Bartoszko JJ, Farooqi MAM, Alhazzani W, Loeb M. Medical masks vs N95 respirators for preventing COVID-19 in healthcare workers: A systematic review and meta-analysis of randomized trials. Influenza Other Respi Viruses. 2020;00:1-9. https://doi.org/10.1111/ irv.12745

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Clinical question What is the role of drugs in preventing covid-19? Why does this matter? There is widespread interest in whether drug interventions can be used for the prevention of covid-19, but there is uncertainty about which drugs, if any, are effective. The first version of this living guideline focuses on the evidence for hydroxychloroquine. Subsequent updates will cover other drugs being investigated for their role in the prevention of covid-19. Recommendation The guideline development panel made a strong recommendation against the use of hydroxychloroquine for individuals who do not have covid-19 (high certainty). How this guideline was created This living guideline is from the World Health Organization (WHO) and provides up to date covid-19 guidance to inform policy and practice worldwide. Magic Evidence Ecosystem Foundation (MAGIC) provided methodological support. A living systematic review with network analysis informed the recommendations. An international guideline development panel of content experts, clinicians, patients, an ethicist and methodologists produced recommendations following standards for trustworthy guideline development using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Understanding the new recommendation The linked systematic review and network meta-analysis (6 trials and 6059 participants) found that hydroxychloroquine had a small or no effect on mortality and admission to hospital (high certainty evidence). There was a small or no effect on laboratory confirmed SARS-CoV-2 infection (moderate certainty evidence) but probably increased adverse events leading to discontinuation (moderate certainty evidence). The panel judged that almost all people would not consider this drug worthwhile. In addition, the panel decided that contextual factors such as resources, feasibility, acceptability, and equity for countries and healthcare systems were unlikely to alter the recommendation. The panel considers that this drug is no longer a research priority and that resources should rather be oriented to evaluate other more promising drugs to prevent covid-19. Updates This is a living guideline. New recommendations will be published in this article and signposted by update notices to this guideline. Readers note This is the first version of the living guideline for drugs to prevent covid-19. It complements the WHO living guideline on drugs to treat covid-19. When citing this article, please consider adding the update number and date of access for clarity.

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Clinical questionWhat is the role of remdesivir in the treatment of severe covid-19? This guideline was triggered by the ACTT-1 trial published in the New England Journal of Medicine on 22 May 2020.Current practiceRemdesivir has received worldwide attention as a potentially effective treatment for severe covid-19. After rapid market approval in the US, remdesivir is already being used in clinical practice.RecommendationsThe guideline panel makes a weak recommendation for the use of remdesivir in severe covid-19 while recommending continuation of active enrolment of patients into ongoing randomised controlled trials examining remdesivir.How this guideline was createdAn international panel of patients, clinicians, and methodologists produced these recommendations in adherence with standards for trustworthy guidelines using the GRADE approach. The recommendations are based on a linked systematic review and network meta-analysis. The panel considered an individual patient perspective and allowed contextual factors (such as resources) to be taken into account for countries and healthcare systems.The evidenceThe linked systematic review (published 31 Jul 2020) identified two randomised trials with 1300 participants, showing low certainty evidence that remdesivir may be effective in reducing time to clinical improvement and may decrease mortality in patients with severe covid-19. Remdesivir probably has no important effect on need for invasive mechanical ventilation. Remdesivir may have little or no effect on hospital length of stay.Understanding the recommendationMost patients with severe covid-19 would likely choose treatment with remdesivir given the potential reduction in time to clinical improvement. However, given the low certainty evidence for critical outcomes and the fact that different perspectives, values, and preferences may alter decisions regarding remdesivir, the panel issued a weak recommendation with strong support for continued recruitment in randomised trials.

Objective To determine and compare the effects of drug prophylaxis on SARS-CoV-2 infection and covid-19. Design Living systematic review and network meta-analysis. Data sources World Health Organization covid-19 database, a comprehensive multilingual source of global covid-19 literature to 25 March 2021, and six additional Chinese databases to 20 February 2021. Study selection Randomised trials of people at risk of covid-19 who were assigned to receive prophylaxis or no prophylaxis (standard care or placebo). Pairs of reviewers independently screened potentially eligible articles. Methods Random effects bayesian network meta-analysis was performed after duplicate data abstraction. Included studies were assessed for risk of bias using a modification of the Cochrane risk of bias 2.0 tool, and certainty of evidence was assessed using the grading of recommendations assessment, development, and evaluation (GRADE) approach. Results The first iteration of this living network meta-analysis includes nine randomised trials—six of hydroxychloroquine (n=6059 participants), one of ivermectin combined with iota-carrageenan (n=234), and two of ivermectin alone (n=540), all compared with standard care or placebo. Two trials (one of ramipril and one of bromhexine hydrochloride) did not meet the sample size requirements for network meta-analysis. Hydroxychloroquine has trivial to no effect on admission to hospital (risk difference 1 fewer per 1000 participants, 95% credible interval 3 fewer to 4 more; high certainty evidence) or mortality (1 fewer per 1000, 2 fewer to 3 more; high certainty). Hydroxychloroquine probably does not reduce the risk of laboratory confirmed SARS-CoV-2 infection (2 more per 1000, 18 fewer to 28 more; moderate certainty), probably increases adverse effects leading to drug discontinuation (19 more per 1000, 1 fewer to 70 more; moderate certainty), and may have trivial to no effect on suspected, probable, or laboratory confirmed SARS-CoV-2 infection (15 fewer per 1000, 64 fewer to 41 more; low certainty). Owing to serious risk of bias and very serious imprecision, and thus very low certainty of evidence, the effects of ivermectin combined with iota-carrageenan on laboratory confirmed covid-19 (52 fewer per 1000, 58 fewer to 37 fewer), ivermectin alone on laboratory confirmed infection (50 fewer per 1000, 59 fewer to 16 fewer) and suspected, probable, or laboratory confirmed infection (159 fewer per 1000, 165 fewer to 144 fewer) remain very uncertain. Conclusions Hydroxychloroquine prophylaxis has trivial to no effect on hospital admission and mortality, probably increases adverse effects, and probably does not reduce the risk of SARS-CoV-2 infection. Because of serious risk of bias and very serious imprecision, it is highly uncertain whether ivermectin combined with iota-carrageenan and ivermectin alone reduce the risk of SARS-CoV-2 infection. Systematic review registration This review was not registered. The protocol established a priori is included as a supplement. Readers’ note This article is a living systematic review that will be updated to reflect emerging evidence. Updates may occur for up to two years from the date of original publication.