Cheap vaccine to prevent cholera

A low-cost oral cholera vaccine can substantially reduce cases of the deadly disease, according to a recent study conducted in Bangladesh.

The vaccine, called Shanchol, can greatly contribute to cholera control efforts in the countries where the disease is endemic, says the icddr,b that conducted the study in the vast slums of Dhaka.

The vaccine costs only Tk 144 or $1.85 per dose and has been prequalified for vaccination programmes by the World Health Organisation as it was proven to be safe and effective in field trials.

The incidence of cholera decreased by more than 50 percent among those who were vaccinated with Shanchol, according to the findings published in The Lancet, a UK medical journal.

The study -- funded by Bill & Melinda Gates Foundation and conducted in collaboration with the health and family welfare ministry of Bangladesh -- was the first effort to give Shanchol through a routine government healthcare to an urban population in constant danger of contracting the disease.

Cholera takes a tremendous toll on public health globally with 91,000 people dying every year, most of them children under five years of age. Around 2.8 million cases of cholera are reported every year and over one billion people are estimated to be at risk, according to the icddr,b.

The success of this vaccine can be a ray of hope for the cholera-endemic countries like Haiti and Zimbabwe.

The study by Dr Firdausi Qadri, director of icddr,b's Centre for Vaccine Sciences, and her colleagues took place between 2011 and 2013 in the urban slums of Mirpur in Dhaka city, an area with a high rate of hospitalisation for severe dehydrating cholera.

"Our findings show that a routine oral cholera vaccination programme in cholera-endemic countries could substantially reduce the burden of disease and greatly contribute to cholera control efforts," said Dr Qadri.

"The vaccine is cheap -- two doses cost around a third of the price of the other licensed vaccine Dukoral," she said.

The research sample included 2,67,270 people who are considered to be at "high risk" because of factors such as living in overcrowded quarters, unsafe sources of water, poor sanitation and unhygienic living conditions.

The researchers aimed to assess the level of protection provided by a two-dose regimen of Shanchol against severe dehydrating cholera. The vaccine was administered through routine government services in the densely populated urban area.

The participants were randomly assigned to one of three groups: those who received Shanchol vaccine, those who received Shanchol and an intervention that encouraged hand-washing and drinking water treatment with chlorine, and those who received no intervention at all.

The results showed the incidence of severely dehydrating cholera was reduced by 37 percent in the overall study population, irrespective of their vaccination status.

The incidence of cholera decreased by 45 percent in the group that received both vaccination and hand-washing-water treatment intervention.

The rate of hospitalisation among those who received the full two doses of the vaccine decreased by more than 50 percent.

For individuals who were vaccinated, it was shown to confer 53 percent protection two years after the vaccine was administered, the study said.

The vaccine was well tolerated with no serious adverse effects reported, according to the icddr,b.