The quest for a malaria vaccine has been underway for a hundred years. Many candidates never made it past clinical trials. On October 6th, however, the World Health Organization endorsed the first ever vaccine to prevent the infectious disease that kills about a half a million people each year, most of them children in sub-Saharan Africa. Called Mosquirix and manufactured by GlaxoSmithKline, the new vaccine triggers the child’s immune system to fight Plasmodium falciparum, the deadliest of the five malaria pathogens and the most prevalent in Africa.
The vaccine is given in three doses between ages five and 17 months, with a fourth dose roughly 18 months later. Following the phase 3 clinical trials, a large scale implementation study was launched in Malawi, Kenya and Ghana, with the goal of assessing the feasibility, safety and impact of the vaccine when administered through the standard immunization programs. More than 2.3 million doses have been administered in those countries, reaching more than 800,000 children. The vaccine decreased severe malaria by approximately 30% and the programs were able to achieve high vaccine coverage, even in the face of the COVID-19 pandemic. A modeling study last year estimated that if Mosquirix were rolled out to countries with the highest incidence of malaria, it could prevent 5.4 million cases and 23,000 deaths in children younger than age five each year.
In commenting on the story from The New York Times, PIDS member Miriam K. Laufer, MD, MPH, a professor of pediatrics and associate dean for student research and education at the University of Maryland School of Medicine said, “The development of the first approved and recommended malaria vaccine has been a long haul for the malaria research community, with so many opportunities to give up. But we did not. Three years ago, we knew that the RTS,S vaccine would protect against malaria disease, but would it be feasible to introduce a 4-dose vaccination into the already stressed immunization programs in sub-Saharan Africa? Would pharmacovigilance systems be able to be developed to detect potential adverse events associated with vaccination? Today, we learned that the answer to both these questions is yes. Malawi, Kenya and Ghana all successfully rolled out these vaccines through their existing public health platforms and created systems to monitor for vaccine safety. The vaccine prevented 30% of the most severe cases of malaria and soon we will learn its impact on child mortality. Today, the WHO was able to recommend RTS,S vaccination to save the lives of children throughout Africa based on rigorous science and strong evidence.”