Costs of diarrhoea and acute respiratory infection attributable to not handwashing: the case of India and China

OBJECTIVE To estimate the national costs relating to diarrhoea and acute respiratory infections from not handwashing with soap after contact with excreta and the costs and benefits of handwashing behaviour change programmes in India and China. METHODS Data on the reduction in risk of diarrhoea and acute respiratory infection attributable to handwashing with soap are used, together with WHO estimates of disability adjusted life years (DALYs) due to diarrhoea and acute respiratory infection, to estimate DALYs due to not handwashing in India and China. Costs and benefits of behaviour change handwashing programmes and the potential returns to investment are estimated valuing DALYs at per capita GDP for each country RESULTS Annual net costs to India from not handwashing are estimated at US$ 23 billion (16– 35) and to China at US$ 12 billion (7-23). Expected net returns to national behaviour change handwashing programmes would be US$ 5.6 billion (3.4-8.6) for India at US$23(16-35) per DALY avoided which represents a 92-fold return to investment, and US$ 2.64 billion (2.08-5.57) for China at US$22(14-31) per DALY avoided– a 35-fold return on investment. CONCLUSION Our results suggest large economic gains relating to decreases in diarrhoea and acute respiratory infection for both India and China from behaviour change programmes to increase handwashing with soap in households. of


Introduction
Handwashing is the most basic and simple element of hygiene and self-care, taught to toddlers and a requisite of many religions, yet studies from both high and low income countries report that as few as 19% of the world's population wash hands with soap following contact with excreta (1).
Handwashing is preventative of many problems including diarrhoea and respiratory infection, in infancy is associated with critical long-term effects on physical and cognitive development (5,6). Proper handwashing after contact with excreta and before preparing and eating meals can lessen the risk of diarrhoea substantially (7) and may also reduce chronic conditions such as environmental enteropathy and lead to better nutrient uptake, more energy for growth and development, and better attendance at school (8). It has been suggested that the costeffectiveness of increasing handwashing is low compared with the cost-effectiveness of oral rehydration (9).
Since Jamieson and colleagues in 2006 (10) suggested that handwashing may be the most costeffective intervention to reduce the global burden of disease, there has been little work on the economics of handwashing, or of not handwashing. Bhutta and colleagues (11) state that the cost-effectiveness of interventions to reduce diarrhoea and pneumonia need urgent assessment and economic evaluation could provide valuable information for policy decisions. This paper addresses the economic issues, summarising recent literature and data on the relationship between handwashing, diarrhoea and acute respiratory infections. It provides estimates of the national costs associated with not washing hands with soap for the world's two most populous countries: India and China, both of which have high rates of these diseases. Data from empirical studies are used to estimate the costs of not handwashing, which are compared with the potential costs and benefits of national behaviour change programmes to increase rates of handwashing. Costs, benefits and returns to investment are presented.

Data sources
The World Health Organisation (WHO) publishes estimates of DALYs for diarrhoea and acute respiratory infection for each country (12). Data from handwashing behaviour change studies in emerging countries allow estimation of DALYs attributable to not handwashing and the financial costs are estimated by valuing each DALY.
Cost of not handwashing = ∑DALYs x attributable fraction x value per DALY This paper estimates the health and economic returns to basic handwashing behaviour change programmes based on the effectiveness and costs of the best published handwashing behaviour change studies, as set out below.
The impact of handwashing on the prevalence of disease Freeman et al (1) reviewed the literature on the health impacts of handwashing, carrying out a random effects meta-analysis from 26 studies. They reported that handwashing with soap results on average in a 40% reduction in risk of diarrhoea (risk ratio 0.60 CI 0.53 -0.68) (1).
The authors were concerned that estimates should be adjusted for any bias due to lack of blinding and made a complex adjustment to 23% (-86%-68%) following the work of Savović (13). The Savovic adjustment was based on very different situations of a wide array of medical interventions, and renders a result which is counter intuitive including a sizable probability of handwashing increasing the risk of diarrhoea by 86% at the 5% level. We therefore use the 40% estimate here which is based on the observational studies and we think the most reliable.
Ensink (14) noted the links between handwashing and acute respiratory infections (ARIs), specifically the presence of respiratory pathogens on hands and environmental surfaces, including the same enteric viruses which cause diarrhoea. We use the published results of a systematic review by Rabie and Curtis (15), estimating that handwashing with soap would be expected to reduce the relative risk of ARI by 16% (6 -40%).

Handwashing prevalence
Freeman et al report also that the average rate of handwashing with soap after using the toilet or being in contact with a child's excreta varied from 5% in Tanzania to 72% in New Zealand (1). Estimates for India were 15% and for China, 13%.

Data on the effects of behavioural interventions
Only a proportion of a population are likely to change their behaviour following targeted interventions; reliable estimates of this proportion are essential for assessing the cost-benefit of interventions. A behaviour change intervention in this context refers to hygiene promotion programmes that aim to improve health by driving the uptake of "healthy" behaviours. A welldesigned behaviour change intervention should have a clearly defined theory-of-change which specifies the behaviour change techniques utilised and maps how individual intervention components are hypothesised to bring about change in the target behaviour (16,17). The intervention should gain attention by causing perceptible changes in the environment, which should cause the recipient to experience the behaviour in a new and rewarding way, which should result in increased practice of the target behaviour (18). Sufficient contact should be made with the target audience over an extended period of time (19).
Luby et al (20) reported that every one of the approached households in a study in Karachi Pakistan (20), participated in their intervention; other studies report lower participation rates.
Biran et al. conducted a review of the levels of handwashing behaviour change that were achieved and sustained and reported by leading studies (personal communication). Many of the studies reviewed relied on self-report which gives a useful indication of trends, but tends to over-estimate prevalence. Three studies however used rigorous designs as well as observation of actual handwashing practice. The magnitude of change achieved in these cluster-randomised control trials, and the before-and-after studies were 11% absolute increase (after cleaning a child's bottom) 18 months after a large-scale programme in Bangladesh) (21), 16-18% after using a toilet or cleaning a child after a 3-year intervention in urban Burkina Faso (22), and 28% after using a toilet, cleaning a child's bottom or handling food, sustained after a year in a trial in rural India (23). Post-intervention prevalence of handwashing with soap after toilet use was 30%, 17% and 29%, respectively giving a mean of 25% which we use here. For the present study, we first carry out a cost analysis to estimate the economic cost of (a) each disease, and (b) of not handwashing. We also present (c) a cost-benefit analysis comparing national costs of programmes to increase handwashing, with the DALYs avoided by the programme translated into monetary values. Programme costs include products and personnel, behaviour change training, and costs of financial incentives and media. Benefits, in terms of DALYs avoided, include improved health, quality of life and life expectancy, improvement in cognitive ability and education for children. Costs and benefits are not easily determined or attributed, but best estimates are made based on results of rigorous empirical studies giving means and 95% confidence intervals.

Disability-Adjusted Life Years or DALYs
The economists have preferred a more conservative valuation, usually at the per capita GDP, the equivalent of a social capital approach. The WHO Commission on Macroeconomics and Health used this approach, defining interventions that avert one DALY for less than the per capita GDP as very "cost effective" (26). This approach has been used also by Brown and colleagues (27) and by Rijo and Ross (28).
Relating the value of a DALY to per capita GDP, means that a rich country with fewer DALYs could be estimated to have higher economic loss than to a poor country with more DALYs, so it is useful for comparative purposes to gauge the economic value as a percentage of each country's GDP (28).
We apply this procedure to the cases of India and China, as the countries with the largest global populations, high DALY losses and low handwashing rates. Costs and benefits are given for one year only, but as the benefits are likely to continue for considerably longer than a year -(research by Cairncross et al 2005(29) suggests for ten years, and in their literature review, Freeman et al (1) report that the impact of the intervention on diarrhoea reduced by only 10% per annum -the benefits are therefore clearly underestimated.

India
India had a population of 1.25 billion and a GDP per capita of US$1584 in 2012, 4% of which was spent on health care (one of the lowest rates in the world and only a third of which was provided publicly) (30). It is a young population with 30% under 14 years of age and 113 million under five years of age. Infant mortality is about 5% and India accounts for over one fifth (21%) of the world's burden of disease (12). Globally about 800 000 or one in ten deaths of those under five are due to diarrhoea, and with nearly 200 000 deaths, India accounts for about a quarter (6). This toll increases to 334 000 if the further 140 000 children dying from complications due to diarrhoea are included (6).
WHO reports that in 2012 the DALYs due to diarrhoea in India amounted to 29.77 million, 14.63 million of which were for infants under five years of age and 3.14 million for children 5 -14 years-of-age (12  The behavioural studies in the section above estimate 40% (CI 32 -47%) of diarrhoea is preventable by handwashing with soap at appropriate times (1). 85% of the general population of India are estimated not to already wash hands appropriately (1), but more of the population contracting diarrhoea will not wash hands and we estimate this to be 90.4%. Were they to wash their hands, their risks would fall by 44% (35 -52%). The cost of diarrhoea by not handwashing is therefore estimated at US$17.07 (13.65 -20. 05) billion (Table 1).

Acute respiratory infection
From the WHO data on burden of disease from ARI for India (12)

Behaviour change interventions
The median level of behaviour change in handwashing intervention programmes is shown to be some 25 % (where soap is provided, it may be as high as 50%   (Table 2) Were the programme focussed on the most affected sectors of the population, such as mothers with children under five years of age, the returns could be proportionally very much higher.  were pneumonia, birth asphyxia and preterm complications (35).
WHO estimates that in 2012 the DALYs due to acute respiratory infections, including pneumonia, totalled 6.32 million, including 3.24 million for infants under five and 0.15 million for children aged 5-14 years (17). China accounts for about 4% of the global burden of acute respiratory infection. (Table 1) DALYs due to diarrhoea amounted to 2.07 million in 2012 (about one tenth that for India), 1.39 of which were for infants under five years of age and 0.08 for children ages 5 -14 years of age. China accounts for about 2% of diarrhoea globally including nearly five percent of the burden relating to children under five years of age (12).

Acute respiratory infection
From the WHO data on burden of disease from ARI for China (12) given in  (Table 2).
For the cost of the behaviour change programme we take the cost for one person per household with children as for India increased by the relative GDP per capita. We estimate that a national programme for China may therefore cost some US$77.72million.
The total net saving to the Chinese economy from a national handwashing behaviour change programme therefore would be an annual US$2.64 (2.08-5.57) billion, or 0.03% (0.02 -0.05%) of the GDP giving a 35-fold return to investment. (Table 2)

Discussion
Handwashing following contact with excreta, the most basic hygiene, is practised by only a fraction of these populations at a high risk in terms of morbidity and mortality from diarrhoea and acute respiratory infections. The longer-term sustainability of interventions that successfully improve handwashing behaviour is rarely studied, but there is some evidence to suggest that high levels of change of 30% can be sustained (19), and that changes can be sustained for many years (1,25). Investment in such programmes nationally would be highly advantageous to the health of these populations, and offer high economic returns to investment.
They are more effective even than programmes to reduce smoking which with success rates of up to 12% are estimated to be highly cost effective (36).
India and China between them make up nearly a quarter of the world's population and India in particular has much to gain, suffering over one fifth of the world's burden of disease and 30% of the global burden of diarrhoea, including nearly half the diarrhoea burden relating to children under five years-of-age and a quarter of infant deaths due to diarrhoea. It accounts for 18% of DALYs from ARI. This compares with 2% of diarrhoea and 4% of ARI for China. China has seen considerable improvements in public health particularly in child health and in reduction in deaths from diarrhoea (31), but these still represent major losses.
This study uses a methodology to assess losses in terms of mortality and morbidity as measured by WHO DALYs, costs these and assesses the cost due to not washing hands with soap.

Limitations
This report is in essence a modelling exercise based on results from primary empirical studies, literature reviews and meta-analyses. We have estimated 95% confidence intervals where possible, but levels of disease and proportions attributable to not handwashing will depend on other factors including provision of clean water and sanitation and improvements in management and treatment. It is possible that few in the rural areas particularly of India seek medical care and as such the costs of care may be lower, but are in any case only a small proportion of the overall cost. There were no data to adjust for the fact that the highest costs would be for the most severe cases of diarrhoea and that some of the DALYs are for children that die?
The estimates are also dependent on WHO estimates of DALYs lost. The costs and benefits are given for just one year, but as the benefits may be far longer lasting, it is suggested up to ten years from time of behaviour change intervention, the cost benefit and returns to investment are likely to be many times more favourable than reported here. Costs of not handwashing are underestimated to the extent that we value a DALY at GPD per capita, whereas WHO recommends two to three times GDP per capita. We have included costs for diarrhoea and ARI only and there would be additional benefits from reductions in other diseases, pandemics of influenza and antimicrobial resistant infections, with untold cost consequences. The estimates of treatment costs, are extrapolated from our relatively small local studies, which it would be important to replicate, although these costs are a small proportion of the total costs. In carrying out national programmes there may be some increasing returns to scale, such as from mass media programmes; there may also be pressure on limited resources, which may increase costs or reduce benefits.

Conclusions
Returns to a national handwashing programme in India could be a net US$5.64(3.38-8.59)) billion with a ninety-two-fold return to the investment, which represents 0.3% of the entire GDP of India. A similar programme for China could result in a net annual benefit of US$2.64 (2.08-5.57) billion representing a 35-fold return on investment.
With these very high estimates of benefits to costs, well designed national handwashing behaviour change programmes in India and China should substantially reduce the heavy burden of disease and offer excellent value for money.

Declarations of Interest
Funding for the authors' time was provided by Unilever PLC which had no input into the paper or influence on the methods, results or conclusions.