Oral cholera vaccine shows promise, finds study
New Delhi: Shanchol, an oral vaccine made by India’s Shantha Biotechnics Ltd, an arm of the French pharma firm Sanofi SA, has reduced cases of cholera by nearly 40% in a trial in Bangladeshi slums, according to a study published in The Lancet on Wednesday.
The results suggest that the vaccine could be used routinely to help endemic countries control the life-threatening disease.
After the first real-life trial, funded by the Bill and Melinda Gates Foundation, researchers said the vaccine proved safe, easy to administer and relatively inexpensive at $1.85 per dose. According to the study, the vaccine worked far better than supplying families with chlorine for their water and soap for hand-washing.
Over 1 billion people are estimated to be at risk of cholera in more than 50 countries where it is endemic. In India alone, a cumulative total of 838,315 cases had been notified to the World Health Organization (WHO) for the period 2004 to 2008, and 676,651 cases were reported from 2000 to 2004. Around 2.8 million cases and 91,000 deaths occur every year in endemic regions, mostly in Asia and Africa.
The vaccine currently being used by the World Health Organization (WHO) since 2001, Dukoral, is an oral cholera vaccine made in Sweden. It is expensive and must be taken with a large glass of buffer solution. Transportation of this solution in areas where the disease is endemic has always posed a challenge and it is thus is useful mostly to wealthy travellers.
Firdausi Qadri, from the International Centre for Diarrhoeal Disease Research, Bangladesh, said, “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.”
The vaccine is cheap; two doses cost US $3.7, around a third of the price of Dukoral he added.
Cholera is an infectious disease that causes acute watery diarrhoea, and spreads through water or food contaminated by Vibrio Cholerae bacteria. Up to 40% of people with cholera develop severe dehydration that, if untreated, can be fatal.
Almost 270,000 residents aged one year and older from the urban slums of Mirpur were involved in the study. Residents were cluster-randomized by dwelling to receive either oral cholera vaccine, and oral cholera vaccine plus a behavioural change programme to improve hand-washing and to provide clean drinking water, or no intervention.
The vaccine was given in two doses 14 days apart through routine government health services.
Vaccination with two doses reduced the overall incidence of severely dehydrating cholera by 37% after two years in the vaccination group and by 45% when used in combination with the hand washing and clean drinking water programme. Analysis of individual protection showed the vaccine gave 53% protection against cholera during the two year follow-up.
The Lancet study also carried a commentary by two epidemiologists from the London School of Hygiene and Tropical Medicine. They said Shanchol had “great potential for aiding disease control” but foresaw obstacles if dosing had to be repeated every five years, so public health campaigns would be needed.
Shantha, acquired by Sanofi in 2009, developed Sanchol in 2009, with assistance from the Bill and Melinda Gates Foundation.