Sanitation vs. vaccination in cholera control

Only weeks away from the launch in India of an oral cholera vaccine significantly cheaper than available vaccines, community workers and health officials are still sceptical of whether a vaccine is the best way to control cholera, according to the International Vaccine Institute (IVI).



IVI’s director John Clemens told IRIN some water and sanitation programme managers argue that the focus in cholera control should be on safe water access rather than vaccine development.



Cholera is a diarrhoeal infection caused by bacteria found in tainted water and food. The disease generally strikes where water supply, sanitation, food safety, and hygiene are inadequate, according to the World Health Organization (WHO).



Introducing a cheaper vaccine in endemic countries “does not mean diminishing the importance of safe water access”, said IVI’s Clemens. “It is a false dichotomy to pit sanitation against vaccination. Improved water and sanitation is the ultimate, but still far-off, goal for impoverished [endemic] countries. Meanwhile we need to think about inexpensive ways to augment efforts [to control cholera].”



Clemens told IRIN that despite a decade of education about the importance of sanitation and safe drinking water, cholera infections have not declined. “Rather, in recent years there have been unprecedented outbreaks of unprecedented duration [in places] where [cholera] had not been [as serious] a problem in recent years.”



Citing northern Vietnam, Angola and Zimbabwe, IVI’s director said being dogmatic about only vaccinations or sanitation can be deadly. “It is erroneous to think about only one intervention. Progressively, people are thinking about how water sanitation and vaccinations can work together.”



More than 6,000 people died from cholera infections worldwide in 2006 – with nine out of 10 infections reported in Africa – according to WHO. But the international health agency estimates that only about 10 percent of cholera infections are ever reported.



In Zimbabwe from August 2008 up to 4 May cholera killed more than 4,000 and infected at least 97,000, according to WHO.



Cost



People living in countries hardest hit by cholera can ill afford the only internationally licensed vaccine sold as Dukarol, Clemens told IRIN. “Travellers [to endemic areas] are the main users, whereas people most affected by cholera go without.”



Dukarol can cost up to US$30 per dose and requires at least two doses with boosters. IVI’s new vaccine, Shanchol, is expected to cost about $1 per dose and calls for two doses.



Other more affordable oral vaccines are not licensed internationally.



IVI’s oral vaccine is in the final phase of a clinical trial in India where 70,000 patients have been tracked since 2006. The manufacturer is expecting to produce five million doses in the first year of immunisations. IVI’s director said the vaccine has not been tested on infants under one year old.



IVI, based in Seoul, South Korea, started cholera research in 1999 with almost $40 million from The Bill & Melinda Gates Foundation. The institute received an additional $20 million in 2006 to introduce a cholera vaccine in endemic countries.



As the cholera vaccine is licensed only in India, IVI will seek WHO’s approval in late 2009.



pt/np