USING EVIDENCE TO DRIVE HEALTH INTERVENTIONS: THE CASE OF
HOUSEHOLD WATER TREATMENT
Thomas Clasen, JD, PhDDepartment of Disease Control
Faculty of Infectious & Tropical DiseasesLondon School of Hygiene & Tropical Medicine
Disclosure/Conflicts
• Unicef• WHO• Unilever• PATH• PSI• Medentech• ICDDR,B• UC Berkeley
• Vestergaard Frandsen• Procter & Gamble• USAID• 3ie• Wellcome Trust• Bill & Melinda Gates
Foundation• American Chemistry
Council
Leading Causes of Deaths from Infectious Diseases
Lower Respiratory Infections
HIV/AIDS DiarrhoealDiseases
Tuberculosis Malaria Measles
Over age 5
Under age 5
De
ath
s i
n m
illi
on
s
Source: WHO 2004
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0 3.9
2.8
1.8
1.6
1.3
0.6
Childhood Mortality by Cause
WHO/UNICEF 2009
Water Supply Coverage
Global Distribution of <5 deaths from diarrhoea
Petri WA, Miller M, Binder HJ et al. (2008). Enteric infections, diarrhoea, and their impact on function and development. J. Clinical Investigation 118:1277-90
Environmental Barriers to Faecal-Oral Transmission
• Primary Barrier– Sanitation (proper
excreta disposal)
– Hygiene (hand washing)
• Secondary Barriers– Water quality
(treatment & safe storage)
– Water quantity (personal and domestic hygiene)
– Hygiene (especially hand washing)
– Proper cooking/food handing practices
Interventions at Source
Benefits of Source-Based Improvements
• Improve water quality– Reduce water-borne diseases
• Improve water quantity and access– Reduce water washed diseases– Improve personal hygiene
• Reduce reported diarrhoea by 30%-45% (Curtis 2005)
• Reduce respiratory infections by 25% (Rabie 2006)
– Improve domestic hygiene– Reduce time spent collecting water– Potential for productive/economic use of water
•An estimated 250,000 hand pumps installed in Africa in 1981-2000•Surveys suggest that less than half were still in use in 2004Harvey and Drouin (2006)
Improved Source ≠ Safe
WHO (2005-6) Rapid Assessment of Drinking Water Quality (n≈1600)
Results of multi-country
Rapid Assessment of Drinking Water Quality (RADWQ)
Percentage of samples from “improved water sources” that comply with WHO DWQG values by country and technology type (compiled from RADWQ reports)
Utility piped water
Community piped
Boreholes/Tubewells
Protected Springs
Protected wells Total
Jordon 99.9% 99.9%
Ethiopia 87.6% 67.9% 43.3% 54.9% 72.0%
Nicaragua 89.9% 39.1% 45.7% 19.3% 46.7%
Nigeria 77.0% 94.0% 56.0% 75.7%
Tajikistan 88.6% 82.0% 87.2%
Systematic Review—Wright et al.*• Systematic review and meta-analysis
of 57 studies measuring bacteria counts for source water and stored water in the home.
• Results: The bacteriological quality of drinking water significantly declined after collection in many settings.
• Conclusion: Policies that aim to improve water quality through source improvements may be compromised by post-collection contamination. Safer household water storage and treatment is recommended to prevent this, together with point-of-use water quality monitoring.
*Wright J, Gundry S, Conroy R (2004). Household drinking water in developing countries: a systematic review of microbiological contamination between source and point-of-use. Tropical Med. Int’l Health 9(1): 106-117
Interventions at the Household
Challenge #1
Assessing Efficacy/Effectiveness
Systematic Review: Fewtrell et al.
Fewtrell L, Kaufmann R, Kay D, Enanoria W, Haller L, Colford J (2005). Water, sanitation, and hygiene interventions to reduce diarrhoea in developing countries: a systematic review and meta-analysis. Lancet Infect. Dis 5: 42-52.
Systematic Review: Clasen et al. (2006)Intervention Type Intervention Type
(no. trials)(no. trials)EstimateEstimate
(random)(random)% % ΔΔ
(1-RR)(1-RR)95% CI of 95% CI of EstimateEstimate
Source (6)Source (6) 0.730.73 27%27% 0.53 to 1.010.53 to 1.01
Household (32)Household (32) 0.530.53 47%47% 0.39 to 0.730.39 to 0.73
Filtration (6)Filtration (6) 0.370.37 63%63% 0.28 to 0.490.28 to 0.49
Chlorination (16)Chlorination (16) 0.630.63 37%37% 0.52 to 0.750.52 to 0.75
Solar Disinfection (2)Solar Disinfection (2) 0.690.69 31%31% 0.63 to 0.740.63 to 0.74
Flocc/Disinfection (7)Flocc/Disinfection (7) 0.480.48 52%52% 0.20 to 1.160.20 to 1.16
Flocc/Disinfection Flocc/Disinfection (ex (ex Doocy)Doocy)
0.690.69 31%31% 0.58 to 0.820.58 to 0.82
Impr. Storage (1)Impr. Storage (1) 0.790.79 21%21% 0.61 to 1.030.61 to 1.03
Clasen T, Roberts I, Rabie T, Schmidt W, Cairncross S. Interventions to Clasen T, Roberts I, Rabie T, Schmidt W, Cairncross S. Interventions to improve water quality for preventing diarrhoea (A Cochrane Review). In: improve water quality for preventing diarrhoea (A Cochrane Review). In: The Cochrane Library, Issue 3, 2006. The Cochrane Library, Issue 3, 2006.
Waddington et al. (2009)
Waddington H, Snilstveit, White H, Fewtrell L (2009). Water, sanitation and hygiene interventions to combat childhood diarrhoea in developing countries. Delhi: International Initiative for Impact Evaluation.
Methodological Quality: Blinding
Clasen et al. 2006
Jain et al. (2009)• Double-blinded, randomized controlled trial of 240
households (3,240 persons) in Ghana using NaDCC + vessel versus placebo + vessel
• Despite high compliance (measured by residual chlorine) and microbiological efficacy, no difference in episodes of diarrhoea
• Researchers cited comparatively high quality water, low rates of diarrhoea and possible protective effect of the vessel
Jain S, Sahanoon OK, Blanton E, Schmitz A, Wannemuehler KA, Hoekstra RM, Quick RE. Sodium dichloroisocyanurate tablets for routine treatment of household drinking water in periurban Ghana: a randomized controlled trial. Am J Trop Med Hyg. 2010 Jan;82(1):16-22
Colford et al. (2009)• Randomized, triple-blinded, crossover trial in 714
households (988 individuals) among older adults in California which used active and sham water filtration devices for 6 months each; outcome=HCGI.
• Incidence rate ratio (active versus sham) 0.85 (95% CI = 0.76, 0.94); longitudinal prevalence ratio 0.84 (95% CI = 0.78, 0.90)..
• Conclusion: “We observed reductions in population- and individual-level measures of HCGI associated with use of the active filtration device.”
Colford JM Jr, Hilton JF, Wright CC, Arnold BF, Saha S, Wade TJ, Scott J, Eisenberg JN (2009). The Sonoma water evaluation trial: a randomized drinking water intervention trial to reduce gastrointestinal illness in older adults . Am J Public Health. 99(11):1988-95.
Boisson et al. 2010• Double-blinded, placebo-controlled RCT among 1144
persons in 240 households in Congo DRC using LifeStraw Family Filter for 12 months (11,236 person weeks).
• Despite strong microbiological performance (2.98 LRV) and relatively high uptake (68%), little evidence of protection against diarrhoea (RR 0.85, 95%CI 0.61-1.20).
• Caveats: placebo was not neutral (1.05 LRV), high non-exclusive use (73% adults, 95% <5s), blinding was not fully successful, and post-hoc analysis showed study was underpowered.
Boisson S, Kiyombo M, Sthreshley L, Tumba S, Makambo J, Clasen T (2010). Field assessment of a novel household-based water filtration device: a randomised, placebo-controlled trial in the Democratic Republic of Congo PLOS One 5(9): e12613
Pending Trial (Clasen et al.)• Double blinded, placebo-controlled RCT in India
among 2000 rural/urban HH with <5s using chlorine tablets (NaDCC) for 12 months
• Setting: High prevalence of DD, relying on unimproved sources, ambient water quality >500 TTC/100ml
• Outcomes: 3-day reported diarrhoea (12 monthly visits), WAZ in <5s, TTC and residual free chlorine, school attendance
• Host: PSI. Funding: PATH, USAID, Medentech, American Chemistry Council
Challenge #2
Correct, consistent use
Compliance• In a systematic systematic review of all HWT
intervention trials, the pooled RR was 0.46 (95%CI:0.25-0.84) among 16 trials reporting compliance >50%, and 0.75 (0.63-0.90) among 5 trials reporting compliance <50% (Clasen 2006).
• Among intervention studies using chlorine,
effectiveness against DD was enhanced among studies with a larger fraction of water samples with detectable free (Arnold 2007).
Filter use: LifeStraw Personal• 171/200 (85%) participants (from 122 households)
interviewed
• Open ended question about last time of use:
• Current user = use in the previous week (34%)
• Consistent user = always drank filtered water + did not drink unfiltered water in previous week (13%)
Boisson S, Tadesse G, Gezahegn H, Gerhanu T, Schmidt W-P, Clasen T (2009). A randomized controlled trial in rural Ethiopia to assess the LifeStraw personal water filter. Environmental Sci. & Tech. 43(15):5934–39
Filter use: LifeStraw Family• Assessed use at month 8 and 14 following deployment in a RCT in Congo
DRC
• Current user (previous week): 82.6% (mo. 8) and 86.8% (mo.14)
• However, among current users, 83.2 % (94.6% of children <5) also reported drinking untreated water the previous day
Boisson S, Kiyombo M, Sthreshley L, Tumba S, Makambo J, Clasen T. Field assessment of a novel household-based water filtration device: a randomised, placebo-controlled trial in the Democratic Republic of Congo (submitted)
Month 8 Month 14
N % N %
Filter present at time of visit 197 82 203 85
Had filter at time of visit 183 93% 192 94
Used filter previous day 107 58.5 138 72.6
Used filter previous week 44 24.1 25 14.2
> 1 week since last use of filter 32 17.5 27 13.8
Programme Assessment: Guatemala • Effectiveness study of a 3-year programme by NGOs in
Guatemala to promote HWT (boiling, Sodis and chlorination) and HWWS
• Six-month study comparing 600 households in 30 matched villages (15 intervention/15 control)
• No statistically meaningful difference in adoption of intervention and control households for HWT (9% vs. 3%) or hand washing with soap (HWWS)
• Consistent with the low sustained behaviour adoption, investigators found no difference between intervention and control villages in child diarrhoea, respiratory infections or growth.
Arnold B, Arana B, Mausezahl D, Hubbard A, Colford J (2009). Evaluation of a pre-existing, 3-year household water treatment and handwashing Int’l J Epidemiology 2009;1–11
Programme Assement: Bolivia• Cluster-randomized controlled trial in 22 rural
communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5.
• A local NGO conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 year.
• Despite the extensive promotion campaign, investigators found only moderate compliance with the intervention (32% regular uses) and no strong evidence of a substantive reduction in diarrhoea among children: RR 0.81 (95% CI 0.59–1.12).
Mausezahl D, Christen A, Duran Pacheco G, Tellez FA, Iriarte M, et al. (2009) Solar Drinking Water Disinfection (SODIS) to Reduce Childhood Diarrhoea in Rural Bolivia: A Cluster-Randomized, Controlled Trial. PLoS Med 6(8): e1000125. doi:10.1371/journal.pmed.1000125
Challenge #3
Effective and appropriate HWT
Interventions at the Household
What about boiling?• Sub-optimal microbiological performance, probably due to recontamination after boiling
• Potentially high cost: US$7.99 to US$8.34 per household per year in India; US$3.24 (collect fuel) to US$20.16 (purchase) in Vietnam
• Indoor air pollution from cooking with biomass associated with reduced birth weight, respiratory infections, anemia, stunting (Retherford 2006)
• Boiling water at home is also associated with higher levels of burn accidents (Rossi 1998). • Other issues: Acceptability, environmental sustainability
Distribution of samples by TTC count (log scale) in longitudinal field studies (n=50 HH in Vietnam and Guatemala, 212 HH in India)
<1 1 to 10 11-100 >100Vietnam (Clasen 2008) 71.2 10.7 13.2 4.9India (Clasen 2009) 37.0 38.3 22.2 2.5Guatemala (Rosa 2010) 59.6 5.7 9.5 25.1Zambia (Psutka 2010) 39.3 22.9 17.7 20.0
The Need for a Technological Breakthrough
• Highly effective against all categories of microbial pathogens
• High capacity (daily and long-term production)• Easy to deploy, learn, use, maintain• Operates in high and variable turbidity• Affordable (up front and long term)• Portable, robust design• Improves water aesthetics• Attractive, aspirational• Protects against recontamination• Reduces arsenic and fluoride• Reduces other chemical contaminants
Challenge #4
Targeting the vulnerable population
Diarrhoea Morbidity
Kosek 2003
Boschi-Pinto 2009
Current Scale of Reported HWT
67%
14%
18%
In an evaluation of JMP household survey data from 67 low and medium-income countries, 33% of households (36.6% urban vs. 30.1%) report treating their water at home before drinking it. This is equivalent to 1.1 billion people.Rosa G, Clasen T (2010). Estimating the scope of household water treatment in low- and middle-income countries. Am. J. Trop. Med. Hyg. 82(2)
Reported microbiologically adequate HWT-use increases with wealth
Rosa G, Clasen T (2010). Estimating the scope of household water treatment in low-and medium-income countries. Am. J. Trop. Med. Hyg. 82(2)
SHG leaders attend information sessions conducted by MFI
Challenge #5
Achieving long-term and sustainable uptake
Sustainability: Arnold et al.
The effect of point-of-use chlorine treatment on child diarrhea by length of intervention. (The area of each circle reflects the study weight in the random effects meta-analysis.)Arnold B, Colford J (2007). Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: A systematic review and meta-analysis. American Journal of Tropical Medicine and Hygiene, 76(2):354–364.
Length of Study (weeks)
Sustainability: (Waddington et al.)
Hunter (2009)
Hunter P (2009). Household water treatment in developing countries: comparing different intervention types using meta-regression. Environ Sci Technol. 43(23):8991-7
Driving HWT Policy with Evidence of Impact*
• Input-based strategy for water (e.g., “improved water supplies”) has led to sub-optimal solutions in terms of performance, health impact and sustainability
• Do not aggravate this problem by counting HWT toward the MDG water target (“sustainable access to safe drinking water’)– HWT does not improve quantity and access, key antecedents
to development (and health)
– Current evidence does not demonstrate that HWT can consistently deliver “safe water” (though safer than some conventional supplies that currently do count)
*Clasen T. Household water treatment and the Millennium Development Goals: keeping the focus on health. Environmental Sci & Tech. 2010 Aug 30. [Epub ahead of print]
Driving HWT Policy with Evidence of Impact
• HWT policy should be assessed on impact (long-term outcomes), particularly on its contribution to health (child survival)– Health-based strategy will require promoters to address key challenges
(efficacy, compliance, performance, target population, sustainable uptake)
– Investment (government, funders, householders) will be commensurate with demonstrable returns
– Position HWT policy in health (rather than water) ministry to develop clear policies that do not divert resources from optimal water solutions (household connections)
• “What gets measured, gets done.” Peter Drucker
Acknowledgements• CDC (S. Luby, R. Quick J. Crump, T. Chiller, E. Mintz, D.
Lantagne)• Proctor & Gamble (G. Allgood, B. Keswick)• WHO (B. Gordon, L. Haller)• Unicef (C. Brockelhurst, O. Odediran)• Eawag/Sandec (M. Weglin, R. Maihofer)• University of Bristol (S. Gundry, J. Wright)• UC Berkeley (J. Colford, B. Arnold)• University of Wales (L. Fewtrell)• University of East Anglia (P. Hunter)• University of North Carolina (M. Sobsey, J. Bartram, J.
Brown)• LSHTM (S. Cairncross, V. Curtis, I. Roberts, T. Rabie, G.
Rosa, L. Smith, W. Schmidt, S. Thomas)
