The Humanitarian Health Evidence Review

The main findings on the effectiveness of WASH interventions in addressing health outcomes in humanitarian settings include:

• The current evidence base on WASH interventions in relation to health outcomes in humanitarian crises is extremely limited (only 6 studies retrieved).
• Numerous methodological limitations (e.g. the use of self-reported diarrhoea and the associated biases, difficulty in blinding study participants, etc.) limit the ability to determine associative, let alone causal, relationships.

There is clearly substantial evidence on the effectiveness of WASH interventions in stable and development contexts. It is also clear that studies on WASH interventions in stable settings help inform future research and practice in humanitarian contexts. Reviews of such studies are available on water (Dangour 2013; Esrey 1991), sanitation (Wolf 2014; Cairncross 2010) and hygiene (Curtis 2003; Freeman 2014), WASH as a whole (DFID 2013), and WASH in complex emergencies (SHARE 2012) (further details are given at the end of this section). However, further studies are required in humanitarian crises given their unique contexts, particularly for supporting the feasibility and cost-effectiveness of WASH interventions in improving health outcomes in these settings.