The rising number of deaths due to cholera has created a need for developing a cheaper and easily accessible vaccine for its control. One such oral vaccine, Dukoral, provided "significant" protection against cholera in a real-life trial in Bangladesh, where the disease kills thousands every year, scientists reported.
The research with nearly 270,000 adults and children in the slums of Mirpur in Dhaka, was the first to demonstrate the drug's effectiveness on-site in an endemic setting, said the authors of a study published in The Lancet.
Such data is crucial for health authorities considering introducing population-wide vaccination programs against the disease that causes acute diarrhoea, and spreads through contaminated food and water.
"Our findings show that a routine oral cholera vaccination program in cholera-endemic countries could substantially reduce the burden of disease and greatly contribute to cholera control efforts," study co-author Firdausi Qadri of the International Center for Diarrhoeal Disease Research Bangladesh said in a statement.
The vaccine, Shanchol, "is cheap", she added. Two doses cost $3.7 (3.4 euros), which is about the third of the price of the only other licensed vaccine, Dukoral.
"Ultimately, the key to controlling cholera is clean water and adequate sanitation, which half the developing world (around 2.5 billion people) lack," said Qadri. "But this remains a rather difficult reality for the world's poorest nations, as well as those affected by climate change, war and natural disasters."
According to the World Health Organization (WHO), the bacterial disease infects about three to five million people every year, and kills an estimated 100,000 to 120,000. For more than a decade, vaccines have been used to protect travellers from rich countries to endemic regions, but not for widespread control.
For the study, Shanchol was given in two doses, 14 days apart, to more than 190,000 people, about half of whom were also enrolled in a programme of "behavioural change" -- hand-washing and home treatment of drinking water. Another 80,000 people were given neither. The vaccines were administered by routine government health services.
Compared to the non-vaccinated group, the overall incidence of "severely dehydrating" cholera was 37 percent lower after two years in the vaccinated group, and 45 percent lower in those who had both the vaccine and the coaching.
There were no serious adverse effects, the team reported.