91,000 people die from cholera every year. Cholera is a burden which is carried by some of the poorest and most vulnerable people in the world. This disease, which puts about 1.4 billion people at risk annually, is most predominant in low-income nations. One of these nations is South Sudan. Since its independence in 2011, South Sudan has been plagued by ongoing conflict, displacements, poverty, and disease outbreaks. In South Sudan’s most recent cholera outbreak, there were already 20,000 cases before the outbreak could be brought under control.
Controlling a cholera outbreak requires a combination of approaches; water and sanitation, hygiene promotion, case management, and reactive vaccination campaigns. The oral cholera vaccine (OCV) revolutionized cholera responses and made it possible protect people from this dangerous disease. OCV campaigns are still incredibly resource intense and traditionally target each person with 2-doses of the vaccine. In places like South Sudan, even reaching these people once is difficult, finding them a second time requires a great deal of motivation, resources, and creativity. In the rainy season, large swaths of South Sudan are flooded and become swamps. This is also the time of year that people are most at risk of cholera. A vaccination campaign requires vaccination teams to literally walk through the swamps for hours, or even days, to reach the affected areas.
Fortunately, a more streamlined approach is possible, and has even been tested in emergency cholera responses in South Sudan. There is a growing body of evidence that supports a single-dose strategy for OCV campaigns. In settings where cholera is endemic, like South Sudan, a single dose of OCV can be as effective as 2 doses for controlling an outbreak. Adopting this strategy would allow the same amount of vaccine to protect double the amount of people. It would also save on the logistical costs of trying to reach each person twice. While a second dose of cholera vaccine makes sense for routine immunization programs because it provides prolonged coverage, it is costly and limiting to an emergency response. In a cholera outbreak, the State Ministries of Health may look to a single-dose strategy to more efficiently control the outbreak and protect their people.