Physical interventions to interrupt or reduce the spread of respiratory viruses. Part 2 - Hand hygiene and other hygiene measures: systematic review and meta-analysis.

Lubna A Al-Ansary; Ghada A Bawazeer; Elaine Beller; Justin Clark; John Conly; Chris Del Mar; Elizabeth Dooley; Eliana Ferroni; Paul Glasziou; Tammy Hoffman; Tom Jefferson; Sarah Thorning; Mieke van Driel; Mark Jones

Five reviewed the evidence in a community setting [70] [71] [72] [73] [74] , and three focussed specifically on children [75] [76] [77] . The earliest review by Rabie et al in 2006 [70] included 8 studies and only 3 were randomised trials. Although each individual study was suggestive of an impact of handwashing on ARI, the pooled estimate of 7 studies was described as "indicative", as studies were few, of poor quality, and limited in geographical scope. The review by Warren-Gash, 2013 [71] included 16 studies (10 were randomised trials), showed mixed results with inconclusive. Wong et al [72] identified 10 RCTs and reported that the combination of hand hygiene with facemasks in the developed countries only (5 trials) had statistically significant effect on reducing laboratory-confirmed influenza (RR = 0.73; 95% CI = 0.53 to 0.99; I2 = 0%; p = 0.05) and ILI outcomes (RR = 0.78; 95% CI = 0.68 to 0.90; I2 = 0%; p = 0.0008), while hand hygiene alone did not show significant reduction in respiratory outcomes. This significant reduction in ILI and influenza for hand hygiene and facemasks was possibly based on the raw numbers without considering any cluster effects in the included cluster trials which produced narrow confidence intervals and possibly biased treatment effect estimates. Moreover, trials from the less developed countries were not included in the review and this significant effect was not sustained when all the trials identified in the review were combined. [73] reviewed all the studies on the effectiveness of personal protective measures (PPM) in interrupting pandemic influenza transmission but identified only 2 randomised trials [46] [78] which reported a significant effect of hand hygiene. In a recent review by Moncion et al [74] , 7 randomised trials of hand hygiene compared to control were identified but the majority did not find statistically significant differences in SARs for laboratory-confirmed or possible influenza between hand hygiene and control groups. Systematic reviews of RCTs on hand hygiene interventions among children [75] [76] or at a non-clinical workplace [77] , identified heterogeneous trials with quality issues including small numbers of clusters and participants, inadequate randomisation and self-reported outcomes.