New Cholera Vaccine: Less Expensive Option to Contain Outbreaks

Though cholera mainly affects children in developing countries, the US is still at risk for outbreaks of this potentially lethal infection following natural disasters or terrorist attacks that disrupt access to clean water and sanitation systems. The manufacture of a safe, rapidly effective oral vaccine will be beneficial for both those in endemic areas and those in non-endemic countries.

Vibrio cholerae bacteria. (Courtesy of cnn.com)

Global Burden of Cholera

Official statistics show that global cholera cases are approximately 200,000-500,000 per year.  However, current research shows that these reported figures only represent 5-10% of actual cholera cases, and it actually affects 3-5 million people and causes over 100,000 deaths per year.

Global Cholera Cases (Courtesy of Who.int)

Water-borne Illness: Public Health Neglect leads to Public Health Crisis

Cholera is caused by a bacterial infection of the small intestine that results in copious watery diarrhea. The diarrhea is so severe that it can result in dehydration, electrolyte imbalances, and even death if not treated immediately.

The infection is spread by ingesting contaminated water or food. In high-income countries, seafood and shellfish are the usual sources, while in low-income countries, water sources are the typical origin of infection. High cholera infection rates in a country are a sign of overcrowding and/or inadequate public health infrastructure, including poor access to clean water and sanitation systems.

Water contamination.

However, natural disasters can disrupt water and sanitation systems in high-income countries, making cholera a potentially devastating infection in the aftermath of a hurricane, tornado, or earthquake.  The WHO Global Task Force on Cholera Control provides a report on using vaccines to control epidemics in Complex Emergencies.

Children are at a higher risk of death from cholera, especially children between two and four years of age. Worldwide, about half of all cases and deaths affect children under the age of five.

Treatment Options

Treatment of cholera infection includes immediately starting oral rehydration therapy (ORT), which is essentially fluid and electrolyte replacement to combat the rapid dehydration caused by the infection. ORT involves drinking water with small amounts of sugar and salt: specifically, 1 liter of boiled water, ½ teaspoon of salt, 6 teaspoons of sugar, and a mashed banana for added potassium. Vitamin and mineral supplementation, particularly zinc supplements, should also be considered following severe infections. If available, Doxycycline is the first-line antibiotic of choice in conjunction with rehydration therapy.  The US Centers for Disease Control (CDC) provides recommendations for treatment options.

Prevention: Infrastructure Improvements and New Vaccines

With so many affected and a disproportionate amount of childhood fatalities, much research has been conducted to develop possible solutions. Without the resources necessary to address the root causes of cholera spread, like building safe and sanitary homes for some of the world’s poorest communities and providing safe drinking water for people living in overcrowded slums, researchers turned to developing a easy to administer vaccine to try and prevent this potentially devastating infection.

In May 2014, Doctors Without Borders reported successful use of Shanchol, an oral cholera vaccine invented in Vietnam and produced in India, to combat a cholera outbreak in Guinea in 2012. The implementation and results of the vaccine program, which was published in the New England Journal of Medicine, showed that the Shanchol vaccine provided protection quickly, making it ideal for future outbreaks. A two-dose vaccine provided close to 86 percent coverage, reducing infection transmission in vaccinated communities.

Oral cholera vaccine. (Courtesy msf.org)

The vaccine has since been stock-piled by the World Health Organization in preparation for emergency use. An older vaccine made by Johnson & Johnson is also available, but the NY Times reports it is more expensive ($5 compared to $2 for Shanchol) and was intended for travelers and not those living in endemic areas.

Report written by Farah Kudrath.

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