At The Mortenson Center blog, we are pleased to continue our series of posts by students of the Center.
Cholera is a waterborne illness that is mainly caused by poor sanitary conditions that expose individuals to the bacterium vibrio cholerae. In many rural parts of the world, flooding at the start of the rainy season exacerbates the spread of the disease. The rainwater builds up in these areas as a consequence of lack of piped drainage systems. This water mixes with sewer and solid waste, thus making the water highly pathogenic. Due to inadequacy of medicines or medical skills, some of these patients do not receive basic treatment and die as a result.
According to the WHO/UNICEF Joint Monitoring program report 2013, 2.4 billion people in the world still lack improved sanitation facilities. Thus, it is not surprising that cholera will continue to be a battle that must be fought, as lives are lost to a preventable disease. Sadly, it seems not to be a battle against death alone, but against the pathogenic microbial world. Studies show that there are new emerging strains of the cholera bacterium. This means that the currently promoted water, sanitation and hygiene (WASH) practices associated with preventing cholera and other water borne illnesses might not suffice in protecting individuals against these new developments. A scientific-based solution such as cholera vaccine(s) may be needed to prevent the disease.
A cholera vaccine was first created in the late 19th century. Like many vaccines, the cholera vaccine is simply a mutated or killed form of the cholera bacterial agent that is ingested to provide immunity through the creation of antibodies. It was originally administered by injection early on but research determined that the vaccine was not as effective in providing immunity as oral vaccines, which are now preferred; injection vaccines have since been phased out. WHO has approved the use of the oral agent brand-named Dukoral which is currently the “vaccine” that is administered in most of the 60 licensed countries.
The oral vaccines provide 2-year protection with an efficacy greater than 50%.
If this immunization were done before the hot and wet seasons, the peak periods when cholera is most likely to break out, the risk of getting cholera would be greatly reduced for many people despite their unsanitary environment. In addition, the vaccine is said to provide “herd immunity” or protection to the non-vaccinated recipients who live in proximity to vaccinated individuals. It was also discovered that the vaccine was just as effective even in an area with widely spread HIV/AIDS. Surprisingly, a study in Vietnam has shown that the cholera vaccines can also be administered during a cholera outbreak and be effective enough to reduce the risk of contracting the disease.
With the use of oral vaccines, the use of intravenous materials such as needles and syringes is totally avoided. Therefore this vaccination minimally contributes to solid waste and can be considered environmentally friendly. Also, taking the vaccine by mouth implies that administering the vaccine is not complex and may not require skillful medical personnel. Instead responsible residents in a particular community can be trained to administer these vaccines and can explain to other dwellers about the vaccines and their significance. This helps to reduce labor as well as transport costs. The vaccines are relatively cheap and one form of the vaccine does not even require water for intake.
Without a doubt, there are some drawbacks such as sustainable refrigeration, social and cultural acceptance (even though field trials have received a positive feedback) and lack of funding for mass campaigns. Despite this, I do believe that cholera vaccines do comply with some of the tenets of sustainable sanitation and hygiene such as the ability to protect human health and the break the cycle of disease, the potential to be used by people of different health states and the potential to be economically viable and socially/culturally acceptable. The vaccine will not replace WASH practices but will certainly avert preventable deaths to some extent.