Oral Rehydration Solution – March 2021 version

This is an interim intervention report. We have published a more recent version of this page, where we consider the benefits alongside therapeutic zinc supplementation. See our most recent report on this program.

Summary

  • What is the program? Oral rehydration solution (ORS) is a type of fluid replacement used to prevent and treat dehydration due to diarrhea.
  • What is its evidence of effectiveness? Our impression is that it is widely accepted that ORS is effective at reducing mortality due to diarrhea. There is strong evidence that ORS is roughly as effective as intravenous fluids at rehydrating children in hospital settings, so we would guess that ORS is highly effective at reducing mortality in hospitals. There are no randomized studies of ORS in community settings, potentially because it would not be possible to get ethical approval for such a trial. Due to the lack of randomized trials, we are uncertain of the likely magnitude of mortality risk reduction in community ORS programs.
  • How cost-effective is it? We estimate that this program is below the range of cost-effectiveness of programs we would direct funding to, but we have enough uncertainty and it is close enough to our threshold that we think additional work is reasonably likely to change our mind.
  • Does it have room for more funding? We have not yet completed a full room for more funding analysis of ORS programs. We believe there may be substantial room for more funding based on conversations with charities implementing ORS programs.
  • Bottom line: This program appears potentially promising, and we may revisit this intervention in the future.


Published: September 2017; Last updated: March 2021 (2017 version)


We revisited the evidence for this intervention in July 2020 and concluded at that time that this report was up to date. We updated the cost-effectiveness sections of this report in March 2021.

Table of Contents

What is the problem?

Diarrheal disease is the frequent passing of loose or liquid stools,1 usually caused by an infection of the intestinal tract.2 Infections are most commonly transmitted through faeces-contaminated water or food.3 Diarrhea generally causes death via severe dehydration and fluid loss, but septic bacterial infections and other causes account for an increasing proportion of deaths.4 Diarrhea is a significant cause of morbidity and mortality in low- and middle-income countries. The World Health Organization (WHO) estimated in 2017 that diarrhea kills about 525,000 children under five years old each year.5 We have not vetted this estimate.

What is the program?

Oral rehydration solution (ORS) is a type of fluid replacement used to prevent and treat dehydration due to diarrhea. ORS programs typically deliver a packet of glucose, sodium, and other minerals in a powder to be dissolved in water.6

The World Health Organization and UNICEF recommend that children with diarrhea take zinc supplements for 10-14 days alongside ORS.7 This report focuses on the evidence for the effectiveness of ORS without zinc supplementation. You can see our report on adding zinc to standard ORS here.

Does the program have strong evidence of effectiveness?

Our impression is that it is widely accepted that ORS is effective at reducing mortality due to diarrhea.8 Due to the lack of randomized controlled trials in community settings, we are uncertain about the magnitude of the effect in those contexts. Below, we discuss the evidence for the effect of ORS on mortality in hospital settings. Our impression is that charities operating in this space will be providing ORS in community settings.

Evidence from hospital settings

The evidence that ORS succeeds at rehydrating children in hospital settings, and is comparably effective to intravenous rehydration, appears to be reasonably strong. Because of its effectiveness in rehydrating children, we would guess that ORS is highly effective at reducing mortality due to diarrhea in hospital settings.

A 2006 Cochrane review (17 trials, 1,811 participants)9 compares oral rehydration therapy with intravenous rehydration therapy in hospitals. It concludes that oral rehydration therapy is comparably effective to intravenous therapy at rehydrating children.10 ORS had a statistically significantly greater chance (4% risk difference, 95% CI 1 to 7) of failing to rehydrate11 than intravenous rehydration therapy.12 The authors conclude this difference was not clinically important.13 15 of the trials were randomized and two were quasi-randomized. The authors note that the trials varied in methodology and quality.14 We have not yet vetted this review or the individual studies included in the review.

How cost-effective is the program?

Based on a cost-effectiveness model we put together in June 2017 and updated with our most recent moral weights as of February 2021, we estimate that ORS is slightly below the range of cost-effectiveness of the opportunities that we expect to direct marginal donations to as of 2021 (about 10x cash or higher);15 however, it is close enough to that range that we believe additional information may change our view. We are highly uncertain about several key inputs in this model, which are dependent on charity-specific information; this model is merely meant to be illustrative of the potential cost-effectiveness of an ORS program. The key assumptions in our CEA are in the following footnote.16

Note that our cost-effectiveness analyses are simplified models that do not take into account a number of factors.17

There are limitations to this kind of cost-effectiveness analysis, and we believe that cost-effectiveness estimates such as these should not be taken literally, due to the significant uncertainty around them. We provide these estimates (a) for comparative purposes and (b) because working on them helps us ensure that we are thinking through as many of the relevant issues as possible.

A number of uncertainties remain that could substantially affect this cost-effectiveness analysis, such as:

  • Magnitude of impact of ORS on mortality in community settings: We have not yet comprehensively reviewed the relevant literature on this question. Due to the lack of high quality randomized evidence on the effect of ORS at reducing mortality in community settings, we are uncertain about the magnitude of the expected effect. We use an estimate of a ~93% reduction in mortality from the most frequently cited meta-analysis we have found, and discount it to account for low evidence quality (discussion in this footnote18 ).
  • Magnitude of increases in ORS coverage attributable to past ORS programs: We are uncertain about the likely counterfactual ORS coverage rates in areas that have been the target of ORS programs.
  • Relative impact of future work: Are future projects likely to be more, less, or similarly cost-effective as past projects?

Organizations that implement this program

We have not conducted a comprehensive search for charities implementing ORS programs. Based on some initial discussions with charities working in this area, we believe there may be room for more funding to support this intervention.

Focus of further investigation

If we were considering recommending a charity working on this program, some questions we may ask as part of further investigation include:

  • How does the quality of ORS treatment in a particular charity's context compare to the quality of treatments provided in ORS studies?
  • Is the quality of treatment likely to be lower for interventions in which caregivers administer ORS rather than community health workers?
  • Does the timing, treatment frequency, and dosage of ORS treatment change its effectiveness?
  • Is ORS similarly effective in homes without access to safe drinking water?
  • Is there additional information that we could gather to better estimate the magnitude of the mortality effect of ORS?

Our process

We searched the Cochrane database for evidence linking ORS to reduced mortality, conducted a brief literature review, and constructed a cost-effectiveness analysis.

Sources

  • 1

    "Diarrhoea is defined as the passage of three or more loose or liquid stools per day (or more frequent passage than is normal for the individual). Frequent passing of formed stools is not diarrhoea, nor is the passing of loose, 'pasty' stools by breastfed babies." WHO - Diarrhoeal disease 2017

  • 2

    "Diarrhoea is usually a symptom of an infection in the intestinal tract, which can be caused by a variety of bacterial, viral and parasitic organisms. Infection is spread through contaminated food or drinking-water, or from person-to-person as a result of poor hygiene." WHO - Diarrhoeal disease 2017

  • 3
    • "Infection: Diarrhoea is a symptom of infections caused by a host of bacterial, viral and parasitic organisms, most of which are spread by faeces-contaminated water. Infection is more common when there is a shortage of adequate sanitation and hygiene and safe water for drinking, cooking and cleaning. Rotavirus and Escherichia coli, are the two most common etiological agents of moderate-to-severe diarrhoea in low-income countries. Other pathogens such as cryptosporidium and shigella species may also be important. Location-specific etiologic patterns also need to be considered." WHO - Diarrhoeal disease 2017
    • "Other causes: Diarrhoeal disease can also spread from person-to-person, aggravated by poor personal hygiene. Food is another major cause of diarrhoea when it is prepared or stored in unhygienic conditions. Unsafe domestic water storage and handling is also an important risk factor. Fish and seafood from polluted water may also contribute to the disease." WHO - Diarrhoeal disease 2017

  • 4

    "Diarrhoeal disease is the second leading cause of death in children under five years old, and is responsible for killing around 525 000 children every year. Diarrhoea can last several days, and can leave the body without the water and salts that are necessary for survival. In the past, for most people, severe dehydration and fluid loss were the main causes of diarrhoea deaths. Now, other causes such as septic bacterial infections are likely to account for an increasing proportion of all diarrhoea-associated deaths. Children who are malnourished or have impaired immunity as well as people living with HIV are most at risk of life-threatening diarrhoea." WHO - Diarrhoeal disease 2017

  • 5

    "Each year diarrhoea kills around 525 000 children under five." WHO - Diarrhoeal disease 2017

  • 6
    • "Dehydration from diarrhoea can be prevented by giving extra fluids at home, or it can be treated simply, effectively, and cheaply in all age-groups and in all but the most severe cases by giving patients by mouth an adequate glucose-electrolyte solution. This way of giving fluids to prevent or treat dehydration is called oral rehydration therapy (ORT)." WHO, Oral Rehydration Salts 2006 report, Pg 1.
    • Note the distinction between oral rehydration therapy (ORT), defined in a WHO report as "The administration of fluid by mouth to prevent or correct the dehydration that is a consequence of diarrhoea" versus oral rehydration salt solution (ORS), defined in the same report as "Specifically, the complete, new WHO/UNICEF formula." WHO, Oral Rehydration Salts 2006 report, Pg iv.
    • "The dose for a one-litre solution of ORS, as provided through UNICEF, has been endorsed by and is used in most countries for the local production of ORS. The dose can, however, be adapted to meet local requirements provided that there is an economic justification for doing so and a prior field study or investigation has shown that the most widely available and best-known containers or receptacles in the households of the country hold a different volume…The recommended formulations of ORS can be produced in three dosage forms: powder, tablet, and liquid. In view of the overriding need to make available an essential drug through the simplest and most appropriate technology at an affordable price, this document deals only with the production of ORS in powder form, which also is the the dosage form on the WHO model list of Essential Medicines…The physical appearance and appeal of an ORS packet are very important for its acceptance in the field." WHO, Oral Rehydration Salts 2006 report, Pgs 6-7.
    • "The amount of ORS solution consumed per day is extremely variable from child to child. Some children with high purging diarrhoea may consume very large amounts of ORS solution." WHO, Oral Rehydration Salts 2006 report, Pg 5.
    • For an example of what an ORS packet looks like, see Image of ORS packet.
    • "The World Health Organization (WHO) introduced the oral rehydration solution (ORS) in 1979, and it rapidly became the cornerstone of programmes for the control of diarrhoeal diseases (Claeson 1990). The osmolarity of the original formulation is 310 mOsm/L (referred to as ORS ≥ 310) and consists of glucose (111 mmol/L), sodium (90 mmol/L), potassium (20 mmol/L), chloride (80 mmol/L), and citrate (10 mmol/L) or bicarbonate (30 mmol/L)…In 2004, the WHO recommended a different formulation in which the glucose and sodium content were each reduced to 75 mmol/L to give a total osmolarity of 245 mOsm/L (referred to as ORS ≤ 270) (WHO 2004). The ORS ≤ 270 reduces stool volume, shortens the duration of diarrhoea, and decreases the need for unscheduled intravenous therapy compared with ORS ≥ 310 (Hahn 2002)." Gregorio et al. 2016, Pg 6.

  • 7
    • "More than 1.5 million children under five continue to die each year as a result of acute diarrhoea. The number can be dramatically reduced through critical therapies such as prevention and treatment of dehydration with ORS and fluids available in the home, breastfeeding, continued feeding, selective use of antibiotics and zinc supplementation for 10–14 days." WHO/UNICEF Joint Statement - Clinical Management of Acute Diarrhoea 2004, Pg 3.
    • "Mothers and other caregivers should…[p]rovide children with 20 mg per day of zinc supplementation for 10–14 days (10 mg per day for infants under six months old)." WHO/UNICEF Joint Statement - Clinical Management of Acute Diarrhoea 2004, Pg 4.
    • "The WHO-recommended treatment for acute diarrheal disease is ORS and zinc supplementation and continued feeding…This combined treatment is highly cost-effective and easily administered by caregivers in the home. WHO and UNICEF have recommended the use of ORS for the treatment of diarrhea since the 1970’s and, in 2004, the two organizations released the Joint Statement for Clinical Management of Acute Diarrhea updating their recommendations.5 Specifically, WHO and UNICEF encouraged the use of a new low-osmolarity ORS (Lo-ORS) formula and included zinc supplementation (see Box 1.1)." @Diarrhea & Pneumonia Working Group 2016 report, Progress over a Decade of Zinc and ORS Scale-up@, Pg 4.

  • 8

    For example, see this quote from a Cochrane review: "Since the 1980s, efforts to reduce the number of deaths from diarrhoea have been based on several interventions, including the improvement of water quality and sanitation, promotion of breastfeeding, and the introduction of treatment programmes that include oral rehydration therapy (Claeson 1990). The World Health Organization (WHO) introduced the oral rehydration solution (ORS) in 1979, and it rapidly became the cornerstone of programmes for the control of diarrhoeal diseases (Claeson 1990). The osmolarity of the original formulation is 310 mOsm/L (referred to as ORS ≥ 310) and consists of glucose (111 mmol/L), sodium (90 mmol/L), potassium (20 mmol/L), chloride (80 mmol/L), and citrate (10 mmol/L) or bicarbonate (30 mmol/L). The ORS was shown to improve signs of dehydration, including thirst, sunken eyeballs, sunken fontanelles, poor skin turgor, or a decreased or absence of urine output (WHO/icddr,b 1995). It was considered to be both safe and effective (Santosham 1991), and mainly responsible for the decrease in case-fatality rates from acute dehydrating diarrhoea (Victora 2000). In 2004, the WHO recommended a different formulation in which the glucose and sodium content were each reduced to 75 mmol/L to give a total osmolarity of 245 mOsm/L (referred to as ORS ≤ 270) (WHO 2004). The ORS ≤ 270 reduces stool volume, shortens the duration of diarrhoea, and decreases the need for unscheduled intravenous therapy compared with ORS ≥ 310 (Hahn 2002)." Gregorio et al. 2016, Pg 6.

  • 9

    "Seventeen trials (1811 participants), of poor to moderate quality, were included." Hartling et al. 2006, Pg 2.

  • 10

    "Dehydration is when body water content is reduced causing dry skin, headaches, sunken eyes, dizziness, confusion, and sometimes death. Children with dehydration due to gastroenteritis need rehydrating either by liquids given by mouth or a tube through the nose, or intravenously. The review of 17 trials (some funded by drug companies) found that the trials were not of high quality; however the evidence suggested that there are no clinically important differences between giving fluids orally or intravenously. For every 25 children treated with fluids given orally, one child would fail and require intravenous rehydration. Further, the results for low osmolarity solutions, the currently recommended treatment by the World Health Organization, showed a lower failure rate for oral rehydration that was not significantly different from that of intravenous rehydration. Oral rehydration should be the first line of treatment in children with mild to moderate dehydration with intravenous therapy being used if the oral route fails. The evidence showed that there may be a higher risk of paralytic ileus with oral rehydration while intravenous therapy carries the risk of phlebitis (ie inflammation of the veins)." Hartling et al. 2006, Pg 2.

  • 11

    "The definition of "failure" varied by study. We evaluated the sensitivity of a more homogeneous definition in which we limited failures to children with persistent vomiting, having some level of dehydration persisting, and experiencing shock or seizures. (We excluded children with paralytic ileus, intussusception, cerebral palsy, septicemia, urinary tract infection, and duodenal ulcer from this analysis.) This post hoc failure definition was statistically significant and favoured IVT for the fixed-effect model (RD 2%, 95% CI +0 to 4) but not for the random-effects model (RD 2%, 95% CI -0 to 4) (Analysis 2.1)." Hartling et al. 2006, Pg 9.

  • 12
    • "Seventeen trials (1811 participants), of poor to moderate quality, were included. There were more treatment failures with ORT (RD 4%, 95% confidence interval (CI) 1 to 7, random-effects model; 1811 participants, 18 trials; NNT = 25)." Hartling et al. 2006, Pg 2.
    • This risk difference implies that if 25 children were treated with ORS, and 25 children were treated with intravenous therapy, one more child would fail to rehydrate on average with ORS than with intravenous therapy.

  • 13

    "Although [there were] no clinically important differences between ORT and IVT, the ORT group did have a higher risk of paralytic ileus, and the IVT group was exposed to risks of intravenous therapy. For every 25 children (95% CI 14 to 100) treated with ORT one would fail and require IVT." Hartling et al. 2006, Pg 2.

  • 14
    • "All trials compared an IVT arm with one or more ORT arms (oral or nasogastric). The trials varied widely in methodology and quality. They were published from 1982 to 2005 and though most were randomized, two trials were quasi-randomized (Singh 1982; Mackenzie 1991)." Hartling et al. 2006, Pg 5.
    • We do not believe the inclusion of quasi-randomized trials had a substantial impact on the results as the two quasi-randomized trials (Singh 1982; Mackenzie 1991) only account for two out of the 66 incidents of failure to rehydrate for ORT, and zero for IVT. Hartling et al. 2006, Analysis 1.1.

  • 15
    See our cost-effectiveness analysis of ORS, “Core calculations” sheet, “ORS vs cash” row.
  • 16

    See Sheets "Notes" and "Parameters," @GiveWell's cost-effectiveness analysis of ORS 2017@.

  • 17

    For example, our current model does not take any benefits from reduced diarrhea morbidity into account, in order to be consistent with our other models (e.g., our insecticide-treated nets model does not directly account for benefits from reduced malaria cases). For other excluded factors, see Sheet "Notes," @GiveWell's cost-effectiveness analysis of ORS 2017@.

  • 18

    Observational case studies and non-randomized trials indicate that increased ORS coverage in the community has been associated with substantial reductions in diarrhea mortality. While we recognize the limitations of this kind of evidence, we believe it is likely that increased ORS coverage causes large reductions in diarrhea mortality. Due to the lack of randomized trials, we are uncertain about the magnitude of this effect, and apply a downward adjustment to the headline result of the non-randomized trials to account for low quality evidence. You can see the assumptions we use in our cost-effectiveness analysis here. Below, we discuss the evidence from (i) a meta-analysis of three non-randomized community trials and (ii) observational case studies of correlations between increasing ORS coverage and reduced diarrhea mortality.

    Evidence from non-randomized comparative community trials:

    • Munos, Walker, and Black 2010, the most frequently cited systematic review of the effectiveness of ORS, included a meta-analysis of ORS reducing mortality in community settings. This estimate seems to be commonly cited in the ORS literature (e.g., it is cited by the Clinton Health Access Initiative and the Lives Saved Tool [LiST]) and is the only meta-analysis of community-based ORS studies that we have been able to find.
      • For the Lives Saved Tool citation, see Lives Saved Tool sources 2010.
      • "The WHO-recommended treatment for acute diarrheal disease is ORS and zinc supplementation and continued feeding. If scaled to 100% coverage, ORS could prevent up to 93% of diarrhea deaths, and zinc can reduce the duration of illness by 25% and prevent recurrence of disease for 2-3 months." @Diarrhea & Pneumonia Working Group 2016 report, Progress over a Decade of Zinc and ORS Scale-up@, Pg 4.
    • The pooled estimate for the effectiveness of ORS interventions (from three studies reporting mortality, 68 total deaths in the studies) found a ~69% decrease in diarrhea mortality (95% CI 51% to 80%) with ~74% ORS coverage.
      • "Diarrhea Mortality (n=3; 68 events). ORS reduces mortality by 69% (95% CI: 51-80%) given mean coverage of 74% (range 52-96%) (93% reduction with 100% coverage)" Munos, Walker, and Black 2010, Pg i80.
    • The authors estimate that 100% coverage would cause a 93% reduction in diarrhea mortality and note that they believe this estimate may be conservative.
      • "We used the pooled effect size for diarrhoea mortality, as it was more conservative than the effect size for severe morbidity (treatment failure). The mean and median coverage levels in the intervention arms of the diarrhoea mortality studies were 74%; assuming a linear relationship between coverage and mortality reduction, at 100% coverage a 93% relative reduction in diarrhoea mortality would be expected (Figure 2)." Munos, Walker, and Black 2010, Pg i78.
      • "We correlated ORS effectiveness with coverage, using the absolute coverage levels reported for the intervention arms. However, in most community-based studies, ORS was also available and used at a low level in the comparison arms. The effective coverage level (difference in coverage between the intervention and comparison arms) was thus lower than the absolute coverage level used in our calculations. For this reason, our approach is conservative and likely overestimates the coverage needed to achieve a particular mortality reduction." Munos, Walker, and Black 2010, Pg i81.
    • Coverage levels in the control group were reported in two of the trials:
      • Kumar, Kumar, and Datta 1987: "ORS was used in 68% and 52% of episodes in the study areas A and B respectively, whereas in the control area it was used in 14% of all episodes…Only 12.5% of male as opposed to 42.8% of female children were not given ORS. Persistent diarrhoea was diagnosed in two cases who received ORS, but died in the study area A and control area." Pg 161.
      • Rahaman et al. 1979: "Consumption of ORS after diarrhoea was 80% in Shamlapur and 38% in Bordil [the control group]. There were 8 deaths in Shamlapur caused by diarrhoea and 23 in Bordil, showing an overall case fatality-rate of 0.5% and 2.4%, respectively" (31 deaths in total). Pg 809.
    • The authors report the evidence was low quality due to non-randomized study designs.
      • "We found a large body of evidence evaluating the efficacy and effectiveness of ORS, and a more limited number of studies assessing RHFs [recommended home fluids]. Based on this evidence, we estimated that ORS may reduce diarrhoea mortality by up to 93%, but were unable to estimate the effectiveness of RHFs against diarrhoea mortality because no studies were conducted outside hospital setting, which is inconsistent with the definition of ‘home fluids’ (Figures 2 and 3). Whereas the overall quality of evidence supporting the effectiveness of ORS against diarrhoea mortality was low as a result of non-randomized study designs, our conclusions are strengthened by the consistency of the effect size and direction among the studies included and those excluded from the meta-analysis. Moreover, the biological basis for ORS, co-transport of glucose and sodium across the epithelial layer in the small intestine is well established and supports a protective effect of ORS against fluid losses and electrolyte imbalances." Munos, Walker, and Black 2010, Pg i81.
    • We have not yet vetted the individual studies included in the meta-analysis.

    Country-level evidence of correlations between rising ORS coverage and declining diarrhea mortality:

    • A 2016 Cochrane review describes ORS as "safe and effective, and mainly responsible for the decrease in case-fatality rates from acute dehydrating diarrhoea."
      • "The ORS was shown to improve signs of dehydration, including thirst, sunken eyeballs, sunken fontanelles, poor skin turgor, or a decreased or absence of urine output (WHO/icddr,b 1995). It was considered to be both safe and effective (Santosham 1991), and mainly responsible for the decrease in case-fatality rates from acute dehydrating diarrhoea (Victora 2000)." Gregorio et al. 2016, Pg 6.
    • The review cites Victora et al. 2000, a collection of four case studies, which find correlations between rising ORS coverage and declining diarrhea mortality in Brazil, the Philippines, Egypt, and Mexico.
      • Brazil: "A simulation model indicated that changes in factors other than ORT explained a 21% reduction in infant mortality attributable to diarrhoea, about a third of the actual decline. Finally, an ecological analysis correlated ORT use rates with proportionate infant mortality caused by diarrhoea, showing a negative association (with r = –0.61 and P = 0.04). Despite the shortcomings of the data these findings suggested an important impact of ORT on mortality attributable to diarrhoea." Victora et al. 2000, Pg 1251.
      • Philippines: "ORT use rates obtained from national surveys in 1985, 1990 and 1993 showed that between a quarter and a third of diarrhoea cases were treated with either ORS solution or RHFs. Death rates associated with diarrhoea fell by about 5% annually from 1975 to 1993 for both infants and children aged 1–4 years, while those for acute respiratory infections fell by 2.9% and 4.0% respectively and mortality caused by perinatal factors declined by 2.6% a year. The proportions of hospital admissions attributable to diarrhoea showed annual declines of 2.5% for infants and 2.4% for children aged 1–4 years. The corresponding figures for admissions associated with acute respiratory infections were 1.8 % and 0.4%. Analyses were made in an attempt to detect significant correlations between proportionate diarrhoea mortality, maternal knowledge of ORS and use rates for ORT (ORS and/or RHFs) in 1993 in the country’s 14 health regions, but none were found. During the study period there were changes in other important variables, including income and the availability of safe water and sanitation, which might have affected mortality associated with diarrhoea." Victora et al. 2000, Pg 1251.
      • Egypt: "ORS was being used to treat between a third and half of all diarrhoea episodes by the late 1980s, thanks to increased availability of the salts, the training of health workers, the education of the general public and other intensive activities…Deaths attributable to diarrhoea among infants fell more rapidly than those attributed to other causes, average annual declines of 4.2%, 7.8% and 15.9% occurring in the periods 1970–77, 1978–83 and 1984–90, respectively. Child mortality caused by diarrhoea showed a similar pattern. There was a marked reduction in the usual summer peak in mortality attributed to diarrhoea among children aged under 5 years. Hospital admissions for severely dehydrated children also fell. Alternative explanations for the improvement were sought. There was some deterioration in socioeconomic status, and changes in water supply or sanitation could not explain the drop in mortality. There was a pronounced increase in the coverage of measles vaccination, but the vaccine was given when most infant deaths had already occurred, i.e. nine months after birth. Regarding nutritional status, there was no change in wasting prevalences but stunting was moderately reduced, perhaps because diarrhoea episodes were less severe. It was concluded that improvements in case management were sufficient to account for most of the reduction in mortality attributable to diarrhoea." Victora et al. 2000, Pgs 1251-1252.
      • Mexico: "National estimates of the use of ORT (ORS solution and/or RHFs) increased from 47.5% of all diarrhoea episodes in 1986 to 80.7% in 1993, while ORS use increased from 24.3% to 41.9%. About half the children given ORT received home-made solutions. The proportion of deaths caused by diarrhoea among children aged under 5 years increased from 24.7% in 1978 to 26.4% in 1983, then declined to 17.2% in 1989 and to 11.0% in 1993." Victora et al. 2000, Pg 1252.
    • The scale-up of ORS in Egypt was also the subject of a Center for Global Development (CGD) case study, which found a decline in diarrhea deaths of ~62%-82% in the same period that ORS coverage increased considerably.
      • "During the peak of the program in the mid- 1980s, the program had achieved a fourfold increase in the distribution of oral rehydration salts, compared with the 1979 baseline…Between 1982 and 1987, infant mortality declined by 36 percent, and child mortality fell by 43 percent. Mortality attributed to diarrhea during this same period fell 82 percent among infants and 62 percent among children." Millions Saved - ORS case study 2007, Pg 1.
      • "In 1982, only 10 percent to 20 percent of diarrhea cases used ORS,6 and most of the ORS lay untouched in warehouses and clinics.5" Millions Saved - ORS case study 2007, Pg 4.
    • We have not yet investigated the case studies in detail or searched for studies published since this review.

Document Source
Diarrhea and Pneumonia Working Group 2016 report, Progress over a Decade of Zinc and ORS Scale-up Source (archive)
GiveWell, Cost-effectiveness analysis, 2020, Version 2 Source
GiveWell, Zinc/ORS CEA, 2021 Source
GiveWell, Zinc/ORS moral weights, 2021 Source
Gregorio et al. 2016 Source (archive)
Hartling et al. 2006 Source (archive)
Image of ORS packet Source
Kumar, Kumar, and Datta 1987 Source (archive)
Lives Saved Tool sources 2010 Source (archive)
Millions Saved - ORS case study 2007 Source
Munos, Walker, and Black 2010 Source (archive)
Rahaman et al. 1979 Source (archive)
Victora et al. 2000 Source (archive)
Walker et al. 2013 Source
WHO - Diarrhoeal disease 2017 Source (archive)
WHO, Oral Rehydration Salts 2006 report Source (archive)
WHO/UNICEF Joint Statement - Clinical Management of Acute Diarrhoea 2004 Source (archive)