BackgroundMore than 761 million people rely on shared sanitation facilities. These have historically been excluded from international sanitation targets, regardless of the service level, due to concerns about acceptability, hygiene and access. In connection with a proposed change in such policy, we undertook this review to identify and summarize existing evidence that compares health outcomes associated with shared sanitation versus individual household latrines.Methods and FindingsShared sanitation included any type of facilities intended for the containment of human faeces and used by more than one household, but excluded public facilities. Health outcomes included diarrhoea, helminth infections, enteric fevers, other faecal-oral diseases, trachoma and adverse maternal or birth outcomes. Studies were included regardless of design, location, language or publication status. Studies were assessed for methodological quality using the STROBE guidelines.Twenty-two studies conducted in 21 countries met the inclusion criteria. Studies show a pattern of increased risk of adverse health outcomes associated with shared sanitation compared to individual household latrines. A meta-analysis of 12 studies reporting on diarrhoea found increased odds of disease associated with reliance on shared sanitation (odds ratio (OR) 1.44, 95% CI: 1.18–1.76).ConclusionEvidence to date does not support a change of existing policy of excluding shared sanitation from the definition of improved sanitation used in international monitoring and targets. However, such evidence is limited, does not adequately address likely confounding, and does not identify potentially important distinctions among types of shared facilities. As reliance on shared sanitation is increasing, further research is necessary to determine the circumstances, if any, under which shared sanitation can offer a safe, appropriate and acceptable alternative to individual household latrines.

Abstract. Shared sanitation is defined as unimproved because of concerns that it creates unsanitary conditions; this policy is being reconsidered. We assessed whether sharing a toilet facility was associated with an increased prevalence of diarrhea among children 5 years of age. We use data from Demographic and Health Surveys conducted in 51 countries. Crude and adjusted prevalence ratios (PRs) for diarrhea, comparing children from households that used a shared facility with children from households that used a non-shared facility, were estimated for each country and pooled across countries. Unadjusted PRs varied across countries, ranging from 2.15 to 0.65. The pooled PR was 1.09; differences in socioeconomic status explained approximately half of this increased prevalence (adjusted PR = 1.05). Shared sanitation appears to be a risk factor for diarrhea although differences in socioeconomic status are important. The heterogeneity across countries, however, suggests that the social and economic context is an important factor.

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Abstract. A large and growing proportion of the global population rely on shared sanitation facilities despite evidence of a potential increased risk of adverse health outcomes compared with individual household latrines (IHLs). We sought to explore differences between households relying on shared sanitation versus IHLs in terms of demographics, sanitation facilities, and fecal exposure. We surveyed 570 households from 30 slums in Orissa, India, to obtain data on demographics, water, sanitation, and hygiene. Latrine spot-checks were conducted to collect data on indicators of use, privacy, and cleanliness. We collected samples of drinking water and hand rinses to assess fecal contamination. Households relying on shared sanitation were poorer and less educated than those accessing IHLs. Individuals in sharing households were more likely to practice open defecation. Shared facilities were less likely to be functional, less clean, and more likely to have feces and flies. No differences in fecal contamination of drinking water or hand-rinse samples were found. Important differences exist among households accessing shared facilities versus IHLs that may partly explain the apparent adverse health outcomes associated with shared sanitation. As these factors may capture differences in risk and promote sanitary improvements, they should be considered in future policy.