When Dr. Johan Strömberg Nörklit, a Swedish physician, first arrived on the island of Zanzibar off the coast of Tanzania in 2000, he was confronted by women who pleaded to be sterilized. He first assumed it was because they lacked access to birth control and wanted to avoid having more children. But when he asked why, their replies shocked him—they said they couldn’t bear to lose more children to malaria.

In Mozambique, one in five children dies by the age of 5. A great many of these children die from malaria, the disease that kills the most African children. About 2,000 African children die from malaria every day.

At the Centro de Investigação em Saude de Manhiça (CISM) in southern Mozambique, where scientists conducted the RTS,S trial, the tragedy of these deaths and the hope that they might be prevented give the work an extraordinary sense of urgency. Everyone who works at CISM knows dozens of families that have been torn apart by malaria. “Those children in the hospital are looking at us, telling us to put more effort, more resources, more brains, more research, to come out with solutions,” the center’s director, Pedro Alonso, has said. “They are a constant reminder of all that needs to be done."

A Growing Problem
In recent decades, drug-resistant strains of malaria emerged, killing more people and further complicating efforts to control and prevent the disease. At the same time, research on malaria vaccines continued to proceed slowly, and it rarely advanced beyond the laboratory and into product development. The commercial market for a vaccine in rich countries is very small—it would consist primarily of the military and travelers willing to take the time and expense to get immunized—so pharmaceutical companies didn’t have a market incentive to concentrate resources on developing one. To make matters worse, the scientific challenges of developing a vaccine for such a biologically complex parasitic disease are immense.

A vaccine isn’t the only way to fight malaria. People can give themselves some protection from the mosquitoes that transmit the disease by sleeping under insecticide-treated bed nets and spraying their homes with insecticides. Drugs can save people who contract malaria. But even a partially effective vaccine would be a major advance in the fight against a disease that infects between 350 and 500 million people every year. The ultimate goal, of course, is a highly effective vaccine that would end malaria as a public health problem.

Next: The Response