A case of cholera can cost a Bangladeshi nearly a month of wages, and as many as 300,000 people in the country suffer from that fate every year.
Not for long. A cheap vaccine has been shown to be effective in a trial of more than 260,000 people.
The trial was conducted in the capital city of Dhaka. A third of those involved in the trial got the vaccine. Another third got the vaccine, and along with that they were offered chlorine treated water to drink and were encouraged to wash their hands with soap more frequently. The remaining third had no intervention.
A two-year follow up found that there were 37% fewer cases in the vaccine-only group and 45% fewer cases in those who got the vaccine along with encouragement to change behaviour, when compared to the group with no intervention. The most severe cases of cholera, which often result in death, were cut by 53% and 57% respectively for the two groups that got the vaccine. The results were published in The Lancet on July 8.
Cholera vaccines have been available since the 1990s. But have not been tested in the countries most affected by the disease, probably because of lack of funding for such large trials. This trial in Dhaka was funded by the Bill and Melinda Gates Foundation.
The vaccine used in the Dhaka trial is called Shanchol, which had shown success in a trial in Kolkata, India. The two vaccine doses required to improve immunity against cholera cost less than $4 in total.
Shanchol was developed by the International Vaccine Institute in 2009 with funds from the Gates Foundation. Since then, it is being manufactured by an Indian company Shantha Biotechnics. The Dhaka trial began in 2011.
The World Health Organization (WHO) receives cholera reports from around the world, but there are often many more unaccounted cases. For instance, in 2011, the WHO reported nearly 600,000 cases and 8,000 deaths in 58 countries. However, the total burden may have been as high as five million cases and 200,000 deaths. Many countries don’t report cases out of fear of travel or trade sanctions.
Moreover, cholera outbreak are quite common after natural disasters. Damaged infrastructure results in poor sanitation, which makes it easy for the bacteria causing cholera to spread. Most recently, Nepal faced such situation after the April 25 earthquake. Now, with access to an effective vaccine, relief efforts would have better chance to deal with the fallout.
Still, as microbiologist Simon Clarke of University of Reading says, “This [trial] is an indication that mass vaccination might have benefits, but it’s no good if you don’t deal with the root cause, which is poor sanitation.”