Inexpensive drug may end cholera epidemics

An inexpensive vaccine for cholera has been found to reduce cases of the disease by almost 40 percent on its own, and by nearly 50 percent when vaccinated individuals also changed behaviors that can spread the disease -- and possibly stop epidemics before they start.

The results of two connected studies showed that vaccinating a large population using normal government vaccination programs can effectively combat cholera where previously the primary method of lowering the spread of the disease was most often focused on improving access to clean water and people's hygienic habits.

Researchers said, in response to the studies, that both are necessary to prevent future epidemics of the disease.

"In the last five years, the conversation has switched from 'We shouldn't use vaccine' to 'How can we use it best?'" Dr. Louise Ivers, a health policy adviser at Partners in Health, an organization that helps to fight cholera and AIDS in Haiti, told the New York Times. "It was reminiscent of the early days of H.I.V., when some people favored prevention over treatment."

Cholera causes severe diarrhea and more than 91,000 deaths per year, often igniting epidemics because of poor hygiene and unclean water.

The traditional method of preventing the spread of the disease has been wider distribution of soap for hand-washing and chlorine to clean water. These methods have been shown in previous studies, and throughout centuries of the cholera epidemics, to be largely ineffective because of the difficulty of changing people's habits in a way widespread enough to control it.

In 2011, researchers conducted a study to find whether it was possible to sufficiently vaccinate a large population by targeting 270,000 people in an urban area of Dhaka, the capital of Bangladesh, to test the effectiveness of the two-dose vaccine, Shanchol.

Participants were split into three groups: One received only the vaccine, one group was given the vaccine as well as soap and chlorine, and another was given only the soap and chlorine. Over the course of two months, 82 percent of participants intended to receive the vaccine got the first of two doses, and 72 percent received the second.

This rate has now been shown in a follow-up study conducted in 2013 to have reduced cholera cases significantly. Researchers found a 37 percent drop in cases among the vaccine-only group and a 45 percent drop for the group that received the vaccine and was counseled in behavioral changes.

The vaccine is inexpensive at $3.70 per two-dose regimen, however the Bill and Melinda Gates Foundation, which funded part of the research, said it is working to get the price below $2 as production increases and it is more widely used.

"Cholera is a huge problem, particularly if there is a natural disaster," Dr. Maureen O'Leary, of the London School of Hygiene and Tropical told the BBC. "You have to view a vaccine as part of an overall package of interventions to reduce cholera, it won't have a huge impact on its own -- but alongside clean water then it can make a big difference."