The cholera vaccine is emerging as a prominent tool in the fight against the disease that the World Health Organization says kills at least 100,000 people every year. WHO is creating a cholera vaccine stockpile that countries can tap into during outbreaks. Health experts say the vaccine is not a panacea and must not detract from prevention basics, like safe water and proper sanitation, but given the extent of cholera’s global impact it is an important tool.
Cholera, silent catastrophe
Advances in vaccine development and promising results in the field have boosted interest in the cholera vaccine. But what really has health ministries and aid agencies increasingly turning to the vaccine is the sheer magnitude of cholera’s impact, in a world where nearly 800 million people live without access to safe drinking water and 2.5 billion without proper sanitation.
Infection is fully preventable; one need simply avoid consuming contaminated food or water. But cholera spreads easily in conditions that are prevalent in much of the developing world: poor sanitation, lack of access to safe water, crowded settlements especially in urban areas, and weak infrastructure that crumbles in recurrent natural disasters.
The World Health Organization estimates that 3 to 5 million people are infected with cholera every year, with as many as 130,000 deaths. Wider use of the WHO-approved oral cholera vaccine - which currently has two manufacturers - is seen as one way to improve the response.
Stephen Martin is with a World Health Organization panel working on the cholera vaccine stockpile. He says the hope is that a stockpile will boost vaccine availability. When Haiti - with a population of nearly 10 million - was hit with a massive cholera epidemic in 2010, there was enough vaccine in the entire world for about 100,000 people.
"The basic reason for a stockpile is that the vaccine and the disease are in two different places and what we're trying to do is bring them together...Cholera - it’s a cliché I'm sure - it’s a disease of the poor, and there is not a strong voice for cholera vaccines. Therefore it makes it very difficult for vaccine producers to have a stable market and that makes it very difficult for them to plan for increased capacity of vaccine production," Martin said. "What we're hoping to do by stabilizing demand is to increase global production capacity."
Proper sanitation, safe water
Health experts say the cholera vaccine must be seen as just one component to be accompanied by other control measures.
"Water and sanitation is key, treatment regimes, epidemiological surveillance, social communication. Those are the four pillars of a standard cholera response. These are the standard responses which work, they've been proven to work," stated Martin. "The sort of holistic approach to a cholera outbreak is to use those four pillars, but now we're saying there is another arrow in the quiver here - there's the possibility of using cholera vaccine as well."
The World Health Organization needs about $4 million to launch the cholera vaccine stockpile, which would initially contain 2 million doses, Martin says. Two doses of the oral cholera vaccine give 60 to 70 percent protection for two to three years.
Medical experts say proper sanitation and safe water are the answer to tackling cholera, but the reality is that global access to these essentials is a long way off.
WHO’s Martin says cholera remains a silent catastrophe. "There are 7 billion people in the world, and 1.4 billion of them are at risk of cholera," he added. "This is a huge number. Where is their voice? Where are these people, demanding water and sanitation and vaccine?"
Cholera experts say given how difficult it is to predict the extent of an outbreak once cholera hits, having a stockpile in place will be just the beginning. Many complex decisions will lie ahead, on when and where to step in with the vaccine.