Bill & Melinda Gates Foundation

One Step Closer: The Search for a Malaria Vaccine

December 17, 2012

Recently, I found myself thinking back ten years ago when my wife and I agreed that the whole family should move to Copenhagen, Denmark, where I had been studying for my PhD. We moved because of malaria.

I had already been living in Copenhagen for a year when I called my wife from a conference in London. She was crying. Our young son, just one year old, had been admitted to hospital with severe malaria. Back then, in 2002-2003, there were so many cases; where we lived in Muheza,Tanzania had a lot of malaria. We decided that we needed to protect our son and slightly older daughter from malaria, as they were at the most vulnerable age.

When I think about the search for a malaria vaccine, I think about most of the parents back home in Africa. Their kids have repeated bouts of malaria – and they do not have the advantage of taking their kids out of a malaria-endemic country. The kids get ill and some of them will die. So it’s very important to me that we develop a vaccine and protect these kids, so that they will reach not only their first birthdays but their tenth and beyond; so they will finish school and work to contribute to their family and national economies.

Malaria is one of the infectious diseases taking a tremendous toll on sub-Saharan Africa. With more than 200 million cases a year around the world, and more than 650,000 deaths, malaria affects the whole family, not only their health but their livelihood. And most of that burden falls on Africa.

Insecticide-treated bed nets are having a positive effect, but they aren’t always available in remote areas and can’t be used 24 hours a day. Yes, if people get sick they are treated, but the parasites are developing resistance to some of the anti-malarial drugs. With spraying, you have to remember that housing standards are not so high in much of Africa, which means that mosquitoes often find their way into homes.

So we need something that prepares the human immune system to battle the malaria parasite. We need a vaccine.

I work on  the RTS,S vaccine – developed by GSK Vaccines, PATH Malaria Vaccine Initiative, and 11 African research centers in seven countries. It is the malaria vaccine candidate furthest along in the development process, in Phase 3 trials. Last year we shared the results of the large-scale, Phase 3 efficacy trial for the older of two age groups, aged 5 to 17 months at the time they received the vaccine. The number of cases of malaria were reduced by half among those receiving RTS,S compared to those receiving another vaccine, over the course of 12 months of follow-up.

This year, we have results from the younger age group, infants aged 6 to 12 weeks when they receive the first of three vaccinations required with RTS,S. For this group, cases of malaria were reduced by one-third when compared to those receiving the non-malaria control vaccine.

So efficacy of this vaccine is a little lower than last year. We don’t have the data to tell us why, but the factors involved are likely to include the great variation in the intensity of malaria transmission across the sites and the presence of antibodies from the mother, passed to the infant, that may inhibit the vaccine’s efficacy.

We will have more data in 2014, when the follow-up of all 15,460 participants has been completed and all the data will be compiled to submit to regulators.

For today, I am just happy and proud to be part of the partnership that exists between MVI, GSK, and we African scientists, that are so thoroughly testing this vaccine and to have the results that we have today. I have been working as a medical doctor for close to 20 years, and in malaria research for 12 years. I have an opportunity that not everyone else has. Getting to a malaria vaccine is hard work, but now we are another step closer.

 
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