May 29,2014
An oral vaccine for cholera has proven to be highly effective and could change the way future outbreaks are controlled. The medical aid group Doctors Without Borders – also known as MSF -- says the vaccine was used during a 2012 outbreak in Guinea.
The study of the oral cholera vaccine known as Shanchol was conducted by Epicentre, the research arm of Doctors Without Borders.
Rebecca Grais, director of epidemiology, said, “I think what’s interesting and what this study adds and that hasn’t been shown up until now is the possibility to include oral cholera vaccine into the arsenal of the epidemic response to cholera. This is the first time that the vaccine was used in sub-Saharan Africa in response to an epidemic.”
The findings are published in the New England Journal of Medicine and Grais said they dispel a number of myths about cholera control.
There was a fear that use of the vaccine would pull resources away from treatment – would be too logistically complicated – and potentially not necessarily have an impact. And what we’ve seen through this study is that it’s effective in terms of protecting individuals in response to an epidemic, but it’s also feasible and did not pull away resources.”
The vaccine is administered in two doses spaced 14-days apart. It had an 86-percent protection rate in Guinea. More than 316, 000 doses were administered over a six week period.
Grais said one advantage of an oral vaccine is that it can be administered by non-medical personnel, as opposed to an injection.
“Second of all, what we’re hoping to do in South Sudan – and what we did do in Guinea – is use the vaccine as part of the response to help bring down the case load, reduce the number of cases. And try and bring a halt to the spread of the epidemic in that environment. And so it does add a new component in terms of response to outbreaks,” she said.
In South Sudan, there’s concern about cholera spreading further among those in crowded camps for the displaced.
Shanchol was not used in the major outbreaks in Haiti in 2011 or Zimbabwe in 2008-2009. There were thousands of deaths in those outbreaks.
Grais said, “The course of those two epidemics may have been very different had the vaccine been used.”
But why wasn’t it used in Haiti and Zimbabwe?
“Like any type of intervention in medicine or in public health, which is until it’s been used, the discussion is extremely difficult to have. Until there’s proof this added intervention is positive with respect to controlling the epidemic it makes the debate very, very difficult because there’s nothing with which to center around or to discuss,” she said.
The World Health Organization is now stockpiling Shanchol – one of two oral cholera vaccines it’s pre-qualified for use. The study says Shanchol is better to use in developing countries because it’s cheaper and easier to manufacture, transport and store.
Cholera is a water-borne disease causing severe diarrhea. It’s usually found in countries with poor sanitation and unsafe drinking water. The disease is usually treated with oral rehydration therapy.
The MSF vaccination project manager in Guinea said, ‘It is possible to vaccinate hundreds of thousands of people in a remote area with a highly mobile population and in a relatively short period of time.”
The group is a major buyer of oral cholera vaccines.