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

Hoffmann, T.; Bakhit, M.; Krzyzaniak, N.; Del Mar, C.; Scott, A.; Glasziou, P.

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.