Soap versus sanitiser for preventing the transmission of acute respiratory infections: a systematic review with meta-analysis and dose-response analysis (preprint)

Objective: To compare the effectiveness of hand hygiene using alcohol-based hand sanitiser to soap and water for preventing the transmission of acute respiratory infections (ARIs), and assess the relationship between the dose of hand hygiene and the number of ARI, influenza-like illness (ILI), or influenza events. Methods: Systematic review of randomised trials that compared a community-based hand hygiene intervention (soap and water, or sanitiser) with a control, or trials that compared sanitiser with soap and water, and measured outcomes of ARI, ILI, or laboratory-confirmed influenza or related consequences. Searches were conducted in CENTRAL, PubMed, Embase, CINAHL and trial registries (April 2020) and data extraction completed by independent pairs of reviewers. Results: Eighteen trials were included. When meta-analysed, three trials of soap and water versus control found a non-significant increase in ARI events (Risk Ratio (RR) 1.23, 95%CI 0.78-1.93); six trials of sanitiser versus control found a significant reduction in ARI events (RR 0.80, 95%CI 0.71-0.89). When hand hygiene dose was plotted against ARI relative risk, no clear dose-response relationship was observable. Four trials were head-to-head comparisons of sanitiser and soap and water but too heterogeneous to pool: two found a significantly greater reduction in the sanitiser group compared to the soap group; two found no significant difference between the intervention arms. Conclusion: Adequately performed hand hygiene, with either soap or sanitiser, reduces the risk of ARI virus transmission, however direct and indirect evidence suggest sanitiser might be more effective in practice.

Downsides of face masks and possible mitigation strategies: a systematic review and meta-analysis (preprint)

ObjectiveTo identify, appraise, and synthesise studies evaluating the downsides of wearing facemasks in any setting. We also discuss potential strategies to mitigate these downsides. MethodsPubMed, Embase, CENTRAL, EuropePMC were searched (inception-18/5/2020), and clinical registries were searched via CENTRAL. We also did forward-backward citation search of the included studies. We included randomised controlled trials and observational studies comparing facemask use to any active intervention or to control. Two author pairs independently screened articles for inclusion, extracted data and assessed the quality of included studies. The primary outcomes were compliance, discomforts, harms, and adverse events of wearing facemasks. FindingsWe screened 5471 articles, including 37 (40 references); 11 were meta-analysed. For mask wear adherence, 47% more people wore facemasks in the facemask group compared to control; adherence was significantly higher (26%) in the surgical/medical mask group than in N95/P2 group. The largest number of studies reported on the discomfort and irritation outcome (20-studies); fewest reported on the misuse of masks, and none reported on mask contamination or risk compensation behaviour. Risk of bias was generally high for blinding of participants and personnel and low for attrition and reporting biases. ConclusionThere are insufficient data to quantify all of the adverse effects that might reduce the acceptability, adherence, and effectiveness of face masks. New research on facemasks should assess and report the harms and downsides. Urgent research is also needed on methods and designs to mitigate the downsides of facemask wearing, particularly the assessment of alternatives such as face shields.