11 May 2014

Africa: The Beauty of Immunization - Why I Work to Develop Malaria Vaccines

Photo: Dave Poland/PATH Malaria Vaccine Initiative
Author Dr. Lucas Otieno Tina


Seattle — This week, we celebrate "Mosquito Week"--but it's not to honor an insect that much of the world considers just a summertime nuisance. It's to remind us that, in fact, the mosquito kills more humans every year than any other animal--more than sharks, more than crocodiles, more than snakes. And for me, it's a reminder of why I do what I do--that is, fighting one of the worst diseases carried by mosquitoes: malaria.

Every day, as a physician and researcher in Kisumu, at the Kenya Medical Research Institute-US Army Medical Research Unit-Kenya collaboration program, I work to protect African children against malaria. And every day, when I see these children and their parents suffering, I feel compelled to do something. First, to treat the disease that kills more than 600,000 people every year--mostly children in sub-Saharan Africa--and second, to prevent it.

In fact, there's a common saying in my community: "It's better to start early than go to a witch doctor." By this, we mean, it's better to prevent the disease than to treat it when it's often too difficult, or too late.

And that is where we find the beauty of immunization with vaccines. We've learned from various diseases, including the classic cases of polio and smallpox, that prevention is better than cure. Vaccination is easier and cheaper than curing, and averts the suffering of the children, and the burden on the family and community.

Across the road from my research center, you will find the Kombewa District Hospital, where we treat the participants who take part in our clinical trials, and other members of the public, for that matter. In the course of my work, I have repeatedly witnessed the problems of poverty, lack of access to proper healthcare and resource limitations. Especially troubling to watch has been overwhelmed medical personnel and facilities struggling with illnesses that are mostly preventable or treatable, primarily infectious diseases--malaria, tuberculosis, diarrhea and HIV/AIDS--and malnutrition.

We've known for 40 years that a vaccine against malaria is biologically feasible. The KEMRI/Walter Reed Project has been in the thick of this research and has worked on malaria and various vaccine candidates for many decades. Through my work with them, I have gained invaluable experience in several large trials of malaria vaccines. I consider our contribution a great achievement given that a malaria vaccine has the potential to change the face of the war against malaria forever.

Today, I'm happy to say, we are completing a Phase 3 clinical trial on the most advanced malaria vaccine candidate to date: RTS,S. No other vaccine candidate has made it this far in the development process. Walter Reed worked with GSK in the early development of RTS,S in the 1980s. In 2009, a unique public/private partnership involving the PATH Malaria Vaccine Initiative (MVI), GSK and 11 African research centers--including my center in Kombewa--launched this large-scale trial with over 15,000 infant and young child participants.

The results so far have been encouraging, with clinical malaria cases reduced by about half in young children ages 5 to17 months old, and by about a quarter in infants 6 to 12 weeks of age, after 18 months of follow-up. We're very much looking forward to the trial's final results, at the end of this year or early 2015, which will provide 30 months of follow-up, and importantly, give us data on the effects of a booster dose.

There are a few things to keep in mind when considering these results:

  • First, if approved by regulators, RTS,S will be the first human vaccine against parasites, making it a significant scientific advance, as well as a public health advance.
  • Second, it is clear that RTS,S is not a silver bullet against malaria. From the start it's been seen as an additional tool--a complementary intervention, if you will--for use in comprehensive approaches to controlling malaria. Such complementary approaches are also seen with other vaccines. For instance, measures to ensure access to clean water and hand-washing, and Oral Rehydration Salts (ORS) complement the use of rotavirus vaccines for diarrhea. With RTS,S, malaria control programs will need to continue to emphasize the use of treated bed nets, indoor residual spraying and rapid diagnosis and treatment of malaria.
  • Third, according to the World Health Organization (WHO), a next generation vaccine following RTS,S is at least 7-10 years away from where RTS,S is TODAY.
  • The Malaria Vaccine Technology Roadmap--a blueprint for developing malaria vaccines--includes a landmark goal, which calls for the licensing of a first-generation malaria vaccine, like RTS,S, with 50 percent efficacy for use alongside existing control measures by 2015.

So where do we see RTS,S in the months to come?

Later this year, GSK plans to submit a regulatory application for RTS,S to the European Medicines Agency (EMA). If the data and public health information is deemed satisfactory, and the EMA gives a positive opinion, the WHO has indicated that a policy recommendation for the RTS,S malaria vaccine candidate is possible by the end of 2015. This would pave the way for local regulatory submissions and decisions by African nations regarding implementation of the vaccine through their national immunization programs.

With this in mind, in Kenya, as in other countries in my part of Africa, like Tanzania and Uganda, efforts are already underway to ensure a timely decision on whether to adopt this new tool, if it is licensed and recommended for use. If we have an effective and approved tool for use against this terrible disease, I'd hate to see it sit on the shelf when I do my rounds in the pediatric ward full of sick kids.

It's been a very gratifying experience to work with WRAIR and our partners on this "big picture" intervention--a vaccine--for one of our biggest and most persistent public health problems--malaria. And I dream that someday, in my community, as well as in others, that that "killer" mosquito will be just a nuisance we can swat away and forget.

Dr. Lucas Otieno is a medical doctor working as a Research Officer and Certified Physician Investigator with the Kenya Medical Research Institute (KEMRI)/Walter Reed Project in Kenya. He is currently a Principal Investigator for the Phase III malaria vaccine trials of RTS,S.

For more information, go to www.malariavaccine.org.

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