The numbers of deaths almost speak for themselves. According to the Global Burden of Disease Study (GBD), malaria killed an estimated 620,000 people in the year 2017, including 350,000 children under the age of 5 — most of them in sub-Saharan Africa.
Although these numbers place malaria near the top of the leading killers of children worldwide, there has also been some progress, with the total number of malaria deaths declining by almost 40 percent over the last decade.
{mosads}The decreases are due in part to poverty reduction and economic growth in many African countries, but also from specific health interventions, including insecticide-treated bed nets, indoor mosquito spraying, and improved access to malaria diagnosis and anti-malarial drugs. Such interventions are publicly supported by the U.S. President’s Malaria Initiative (PMI) and the British Department for International Development, together with the Global Fund to Fight AIDS, Tuberculosis, and Malaria (GFATM) and other organizations.
While lives have been saved, the overall progress in the fight against malaria is still slow, and it would be great to have in-hand a game-changing technology to accelerate future public health gains. From the lessons learned through reducing childhood deaths from measles, whooping cough, tetanus, Hib and other infections, the most effective way to save lives is through the development, testing and ultimately introduction of a vaccine.
For malaria, several vaccines are in different stages of product and clinical development, but the one furthest along is known as RTS,S, which was originally developed by the U.S. Army through the Walter Reed Army Institute of Research (WRAIR), and later advanced by a global partnership between the non-profits PATH and the Bill & Melinda Gates Foundation, a network of African research centers and universities, and the pharma giant, GlaxoSmithKline.
Now, more than 20 years after the RTS,S malaria vaccine first underwent clinical and safety testing the World Health Organization has announced that Malawi will become the first of three sub-Saharan African nations (followed by Ghana and Kenya) to launch a pilot program of vaccine evaluation. Among the highlights of the pilot program, it will first assess the feasibility of administering all of the required vaccine doses (4) in a real life setting, and then confirm both the safety of the vaccine and its ability to reduce childhood deaths. Initial support for the three-nation pilot program will come from commitments by GFATM, Gavi, the Vaccine Alliance and Unitaid.
There are several complicated aspects to these African vaccine introductions. For instance, administering four doses of a vaccine and then ensuring all of the children are adequately followed and evaluated medically is a logistical challenge in a resource poor setting and often depleted health system. Another is the sheer size of the effort — more than 350,000 children will receive the RTS,S vaccine in the three pilot countries.
Also a pressing issue is the finding that during advanced clinical testing the vaccine was found to be effective, but not nearly as effective as other childhood vaccinations. For example two doses of the measles vaccines provides up to 97 percent protection against measles, whereas even after four doses of RTS,S, the vaccine protects only 40 percent (4 in 10) of children against becoming infected with malaria (over a four-year period) and only 30 percent (3 in 10) of children from life-threatening malaria cases.
Practically speaking this means that RTS, S will not replace bed nets, anti-malarial drugs, and other public health measures. Instead it will complement or augment these current public health approaches.
The delivery of a partially-protective vaccine being used alongside of existing measures is a relatively new idea in the global health community, and one that might take time for policy makers to accept. But it’s one that we’ll need to get used to. Although other malaria vaccines are under development, including a whole cell malaria vaccine, which might offer better protection than RTS,S, the fact is that many of our next generation vaccines, such as those for HIV/AIDS and tuberculosis will also be partially protective, as might the new vaccines to prevent worm infections that we’re developing in our Texas Children’s Hospital Center for Vaccine Development. We may need to adjust the framework of our current health systems to accommodate vaccines as complementary rather than as replacement biotechnologies.
The community of global health scientists and public health experts are excited about the potential of introducing the first malaria vaccines for Africa. I hope it becomes the first of several new vaccines to come online for the world’s most prevalent neglected diseases.
Peter J. Hotez M.D., Ph.D., is a vaccine scientist, professor of pediatrics and dean of the National School of Tropical Medicine at Baylor College of Medicine His latest book is “Vaccines Did Not Cause Rachel’s Autism: My Journey as Vaccine Scientist, Pediatrician, and Autism Dad.”