A low-cost, oral cholera vaccine may be able to protect entire communities in densely populated areas from the deadly disease. A recent trial in Bangladeshi slums has shown the effectiveness of this vaccine in a real-life situation by reducing the incidence of severe cholera by nearly 40%.
Cholera is endemic in Bangladesh, which has an estimated 300,000 cases and 4,500 deaths each year. It is often described as a disease of poverty that particularly affects young children.
The oral vaccine – called Shanchol – could help overcome the financial cost of the disease, which is a major cause of morbidity and mortality in low-income countries. Researchers trialled the vaccine between 2011 and 2013 on almost 270,000 residents in the urban slums of Mirpur in Dhaka city.
“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 around a third of the price of the other licensed vaccine Dukoral,” Dr. Firdausi Qadri of the International Centre for Diarrhoeal Disease Research said in a statement.
The study, published in The Lancet, showed that two doses of the vaccine reduced the incidence of severely dehydrating cholera by 37% and when combined with hand-washing, the incidence was further reduced to 45%. The vaccine was shown to give 53% protection two years after it was administered.
Shanchol also overcomes some of the significant drawbacks of other cholera vaccines, researchers say. Injected vaccines, though still manufactured in some countries, are not currently recommended by the World Health Organization as they provide limited protection against the disease. The Shanchol vaccine also only costs $3.70 for two doses.
Simon Clarke, an expert in cellular microbiology at Britain's University of Reading, told Reuters UK: “Developing new, safe, longer-lasting vaccines which can be widely and easily administered is therefore vital ... (and) this vaccine could be a powerful weapon.”
Qadri stressed that while the vaccine would be beneficial, “ultimately, the key to controlling cholera is clean water, improved hygiene practices and adequate sanitation facilities.” These improvements would require a great deal of large investments, but major infrastructural changes are vital to protect people from the devastating impact of the disease, she added.