The transmission dynamics and vaccination coverage of cholera in Haiti are examined in a modelling paper published in Scientific Reports this week. The study, which suggests that 46% vaccination coverage would be sufficient to control the disease in the country, could be used to help to plan and evaluate disease-control interventions, including vaccination.
In October 2010, Haiti reported cholera cases for the first time in decades, with cases first appearing in the Artibonite region, a rural area north of Port-au-Prince, and then spreading throughout the country. Zindoga Mukandavire and colleagues used a mathematical model originally developed for the 2008-2009 cholera outbreak in Zimbabwe to quantify the magnitude of outbreaks of the disease in Haiti and to estimate vaccination coverage. The authors calculated the basic reproductive numbers for Haiti - the number of cases each case generates over the course of its infectious period. The estimated basic reproductive numbers varied across the country’s departments, from 1.06 to 2.63 - similar to estimates obtained for the 2008-2009 Zimbabwe outbreak - highlighting the geographical variability in the initial Haitian epidemic and corresponding variability in the necessary vaccination coverage for effective disease control. At a national level, 46% vaccination coverage woul d be sufficient to lower the basic reproductive number to a level low enough to suppress transmission, the team report.
The results suggest that vaccination and other interventions that permanently reduce transmission could have a major impact on long-term cholera management in Haiti.