Table 3 Reduction in transmission coefficient (“contact rate”) by water, sanitation and hygiene (WASH) interventions in selected published models of the Haiti epidemic
From: Cholera transmission dynamic models for public health practitioners
| Model | WASH intervention that the model was supposed to simulate | Reduction in transmission coefficient (“contact” rate, β) | Empirical data sources for WASH interventions’ effectiveness or coverage |
|---|---|---|---|
| Andrews and Basu [11] | Expansion of clean water provision | Exponential decline in β (1% decrease per week) | Estimated coverage of clean water since the outbreak’s beginning, from two progress reports by Red Cross and Oxfam respectively |
| Bertuzzo et al. [12] | Sanitation: “a set of measures”, not explained in their paper | 40% reduction for 1 month | None provided |
| Chao et al. [9] | Educational campaign to promote improved hygiene and sanitation, that accompanies the vaccination campaign | 10% or 30% (additional) reduction, in areas covered by vaccination campaign | None provided |
| Tuite et al. [10] | Clean water provision, either to “the same number of people who could be vaccinated” or to “the number of people who would need to receive clean water to have the same effect on epidemic spread as that achievable through vaccination” | Reduction of waterborne transmission (but not human-to-human transmission) by a fraction that is the probability of provision of clean water within a Haitian department (equivalent to a province), for up to 2 years, beginning at the same time as vaccination program would do for the sake of comparison. | None provided. Implied assumption: 100% reduction of “contact” rate if covered by clean water provision. |