Limiting Cholera With Limited Vaccinations

U.S. researchers, using data from Bangladesh, have developed a mathematical model predicting control of cholera with less than total vaccination.

The study, published in the journal PLoS Medicine, predicts cholera outbreaks in the Matlab region could be controlled by vaccinating only half of the population.

Study leader Ira Longini of the University of Washington School of Public Health and Community Medicine in Seattle predicts that thanks to herd immunity — protection of the unvaccinated because those who are vaccinated no longer expose them to infection — vaccinating only 50 percent could reduce cholera cases among the unvaccinated in the region by 89 percent. As a result, total population reduction of cholera would be 93 percent.

The model predicts reducing the number of cases of cholera by three-quarters if only one-third of the population is vaccinated.

Cholera — best prevented by full access to safe water and good sanitation — is still found in many countries and in situations of population displacement such as refugee camps and disasters such as floods.