Modeling the Effect of Water, Sanitation and Hygiene and Oral Cholera Vaccine Implementation in Haiti

In 2010, epidemic cholera was introduced to Haiti. Because resources are scarce, decision-makers need to understand the effect of different preventive interventions for ongoing transmission. We built a static model to estimate the potential number of cases averted by water and sanitation improvements (WASH) (i.e., latrines, point-of-use chlorination, and piped water), oral cholera vaccine (OCV), or a combination of both. We allowed for indirect effects and used non-linear relationships between effect and population coverage. We applied 1990-2010 cholera incidence data from Malawi to Haitian demographic data to estimate the potential annual incidence of endemic cholera for a 20-year period in Haiti. We modeled 16 scenarios: six WASH, six OCV, and four that combined WASH and OCV. Over the next two decades, scalable WASH interventions could avert from 57,949 to 78,567 cholera cases, OCV 38,569 to 77,636 cases, and interventions that combined WASH and OCV 71,586 to 88,974 cases. Rate of implementation is the most influential variable, and combined approaches maximized the effect