April 13, 2012 |

The lure of a malaria vaccine

When Dr. David Kaslow joined the PATH Malaria Vaccine Initiative (MVI) as director recently, he continued a professional career notable for his commitment to understanding the malaria parasite and developing a human vaccine against it. In advance of World Malaria Day on April 25, Dr. Kaslow answered a few questions about malaria, vaccine, and his work.

Q. You have a long history of working to develop an effective vaccine against malaria. How did you get started in the field, and what keeps you at it?

Mother and toddler sit in front of blister pack of medication.
Testing for malaria in Zambia. Photo: PATH/Gena Morgan.

A. Although I’m a physician trained in human genetics, my scientific career has focused on infectious diseases, starting at NIH (National Institutes of Health) in basic research studying the biology of the malaria parasite, in particular the stages that transmit the parasite from humans to mosquitoes.

After 13 years at NIH, I decided to learn industrial-strength vaccine development, both in big pharma and biotech. When the exciting opportunity arose to join the MVI team, I couldn’t resist picking up where I left off 13 years ago with malaria vaccine research and development. I’m very excited about MVI’s role in producing what could be the world’s first human vaccine against a parasite, a malaria vaccine candidate called RTS,S. I’m also excited about the prospects of next-generation malaria vaccines that either build off of RTS,S or use such innovative approaches as blocking the transmission of malaria between mosquitoes and people, thus breaking the disease cycle altogether.

Q. Malaria presents particularly thorny challenges when it comes to developing a vaccine. How do you feel about progress so far?

A. Malaria is caused by parasites with very complex life cycles that evolved in part to evade the human immune system. This makes developing vaccines for the major forms of human malaria an extremely daunting challenge for the scientific community. With the RTS,S vaccine candidate, we have compelling initial data that it is possible to protect about 50 percent of vaccinated young children from clinical disease. If confirmed by the results yet to come, this would be a major scientific breakthrough! After long years of arduous research, we appear to have a tool to work with to develop even more effective vaccines against malaria.

Q. When do you think we’ll see a widely distributed vaccine against malaria? What has to happen next?

A. If all goes well with the Phase 3 trials, the European Medicines Agency and World Health Organization will review the RTS,S results in 2014 and 2015. If they reach positive conclusions regarding RTS,S, national African regulatory agencies and policymakers will decide whether and how to implement the vaccine within their countries.

As 2014-2015 approaches, it will be critically important that countries have the necessary financing lined up to obtain the vaccine, whether through global health organizations like the GAVI Alliance, through other funding partners or, for a few wealthier countries, from their own resources. MVI is already working to help make this happen.

Q. What kind of a difference do you think such a vaccine will make in the lives of people in malaria-endemic regions?

A. We’re all aware of the huge number of illnesses and deaths attributable to malaria worldwide and its economic and social impact. But I think we greatly underestimate the burden of malaria on individuals and families, and their communities. The severe form of the disease hits the most vulnerable—the very young. The death of a child due to malaria is devastating for a family.

A child sickened by malaria also inflicts a great burden on the parents, who often have very limited means and resources. Instead of tending their fields or going to work elsewhere, they are home taking care of the sick child or going the multiple miles to the nearest health center for treatment. Children with milder cases can’t perform well at school or help with the household chores. The work of the adults carrying the parasites is also affected. When a community is struck with a wave of malaria, say during the rainy season, the health services are frequently overwhelmed and the community’s economy suffers.

A vaccine that significantly reduces the number of childhood cases of malaria would have a positive impact at many levels.

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  • Dr. David Kaslow is vice president of Essential Medicines and director of the Center for Vaccine Innovation and Access at PATH.