-By Samantha Venkatesh
When I traveled to India for the first time in 2005, the last thing I expected to do before my summer vacation was take medication. I distinctly recall my mom handing me a pill box and instructing me to take the medicine daily starting a few days before we left, through the month-long trip, and for a week after we returned. As a ten year old, this seemed overly complicated and unnecessary. In retrospect, I am relieved that my mom remembered this seemingly annoying task, especially considering that my entire body was covered in mosquito bites after the trip. She was able to prevent me from getting malaria, one of the most severe tropical illnesses in the world.
Malaria is a mosquito-borne illness that is caused by species of the parasite Plasmodium and is spread by the bites of the mosquito species Anopheles1. Since 2000, the World Health Organization has been actively attempting to reduce the incidence of malaria worldwide by seventy-five percent as one of its Millennium Development Goals (MDGs)1. To some extent, the WHO has succeeded; estimated malaria mortality decreased by forty-five percent overall in the last decade alone2. But the disease still impacts almost half of the world; more than three billion people are at risk of contracting malaria, and in 2010, there were an estimated 207 million cases globally3.
Over this summer, I traveled to India once again, and I had to retake the course of medicine to prevent the illness. Though the efficacy of the medication is high, having to take it every single time I travel is somewhat of an inconvenience. That being said, I was quite interested when I recently read in the New York Times that GlaxoSmithKline is in the process of testing a malaria vaccine and is considering submitting it for review this year so that the vaccine may be disseminated as early as 20154. A single vaccination that would prevent the illness over an entire lifetime would be a marked leap in malaria eradication. Though a number of treatments and prevention measures are available to combat the disease, including drugs, insecticides, and mosquito nets, none would be as effective as lasting immunity. The development of the vaccine in question, called RTS,S, was funded by the Bill and Melinda Gates foundation, and would be the first vaccine approved to target a parasitic infection4. It targets the deadliest malaria parasite Plasmodium falciparum at the beginning of its life stage, prior to entering the blood stream and multiplying4.
This is undoubtedly groundbreaking for the scientific community, but the current practicality of the vaccine is questionable. Promising, but not miraculous, statistics from the vaccine trials on infants indicated that it was only 30% effective in protecting African babies from ages 5 to 17 months, and it reduced the risk of severe malaria by just 45%5. Even more troubling is the fact that the New England Journal of Medicine found that protection from the vaccine was short-lived. The vaccine’s effectiveness began to diminish eight months after administration, and after four years, the vaccine’s efficacy declined to a mere 17%6.
Nevertheless, Glaxo Smith Kline is looking for approval from the European Medicine Agency in hopes that the World Health Organization will approve RTS,S for global use in children by 2015. But will this intervention be helpful? Public health officials will soon have to decide whether the vaccine should be adopted and distributed as part of malarial prevention programs. Considering the enormous sums of funding that would be needed, this decision will not come lightly. Some officials may consider that the merit of immunity should not be ignored. The majority of malaria deaths occur in children, who have not had years of exposure to gain even minor immunity like adults have. A vaccine would greatly assist this most vulnerable population. Researchers argue that even a 30% reduction rate is significant considering the vast number of people that are at risk to contract malaria- hundreds of thousands of deaths would still be prevented5. Not only is malaria severe in terms of symptoms and mortality, but it can also be contracted multiple times within a short time span, and a long-lasting solution would be more beneficial than attempting to treat the illness every time someone is infected. In addition, though anti-malarial drugs are readily available, their efficacy is declining in the wake of drug-resistant strains of malaria7. A vaccine could be the solution to this growing problem and may combat these hybrid strains.
In reality, however, mass vaccinations of RTS,S may not hold up to its potential. Countries would need to invest significant amounts of funding to purchase the vaccine, but with an efficacy of only 30-45%, this might be a cost that may not be entirely beneficial. The low efficacy rates coupled with a short window of immunity is perhaps not the right option for nations seeking to decrease their rates of disease. The vaccine is predicted to be marketed for a few dollars per injection8: this could be too expensive for nations searching for cheaper alternatives to prevent malaria infection. Commonly-used anti-malarial drugs only cost a few cents per round of treatment and might be a more feasible option for poorer nations. Other prevention methods, such as providing education about mosquito nets and repellents, along with anti-malarial prescriptions may prove to be more economical in the short run.
Perhaps the most effective option, however, would simply be to wait for a more effective malaria vaccine. Existing malaria treatment options should be utilized and exhausted until RTS,S becomes more potent or is accompanied by a booster vaccine. Though this may require a bit of patience, the benefits in the long term of mass vaccination trump the temporary costs and would provide a more lasting solution to this rampant disease.
- Malaria Facts. (2012, September 19).Centers for Disease Control and Prevention. Retrieved February 11, 2014, from http://www.cdc.gov/malaria/about/facts.html
- MDG 6: combat HIV/AIDS, malaria and other diseases. (n.d.). World Health Organization. Retrieved February 14, 2014, from http://www.who.int/topics/millennium_development_goals/diseases/en/
- Malaria. (n.d.). World Health Organization. Retrieved February 12, 2014, from http://www.who.int/mediacentre/factsheets/fs094/en/index.html
- The Editorial Board (2013, October 13). Hope for a Malaria Vaccine. The New York Times, p. A24. Retrieved February 11, 2014, from http://www.nytimes.com/2013/10/14/opinion/hope-for-a-malaria-vaccine.html?_r=0
- Malaria vaccine candidate reduces disease over 18 months of follow-up in late-stage study of more than 15,000 infants and young children. (2013, October 7). GlaxoSmithKline. Retrieved February 14, 2014, from http://www.gsk.com/media/press-releases/2013/malaria-vaccine-candidate-reduces-disease-over-18-months-of-foll.html
- Olotu, A., Marsh, K., Fegan, G., Bejon, P., Peshu, N., Njuguna, P., et al. (2013). Four-Year Efficacy of RTS,S/AS01E and Its Interaction with Malaria Exposure.New England Journal of Medicine,368(12), 1111-1120.
- Walsh, Bryan. Drug resistant malaria is spreading, and it could be a public health disaster. (2012, April 6). TIME. Retrieved February 13, 2014, from http://healthland.time.com/2012/04/06/drug-resistant-malaria-is-spreading-and-it-could-be-a-public-health-disaster/
- Knox, Richard. First malaria vaccine moves a step closer to approval. (2013, October 8). NPR. Retrieved February 14, 2014, from http://www.npr.org/blogs/health/2013/10/08/230356317/first-malaria-vaccine-moves-a-step-closer-to-approval