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Trial starts of malaria vaccine in 2000 children in Mozambique

Anne Gulland London

Researchers hope to see the first results from the largest ever malaria vaccine trial in children in Africa in just 18 months, the research team leader announced last week.

Phase two clinical trials of the most advanced malaria vaccine were due to start last Monday in 2000 children aged between 1 and 4 years in Mozambique.

Pedro Alonso, head of the Centre for International Health at the University of Barcelona, Spain, and principal investigator of the vaccine trial, told a press conference earlier this week: "The screening of the children has been completed, and we hope to have the results one and a half years from now. What’s ahead of us is a lot of work ensuring the safety of the participants."

The RTS,S/AS02A vaccine was developed by GlaxoSmithKline Biological, and the $6.7m (£4.1m; €5.9m) trial is being funded by the Malaria Vaccine Initiative, a non-profit organisation. It has already been tested on both immune and non-immune adults in Kenya, Gambia, the United States, and Belgium. Researchers in Gambia found that 71% of adults who were vaccinated were protected from developing malaria in the short term (Lancet 2001;358:1927-34).

The trial will be a randomised control trial with the aim of assessing the safety and efficacy of the vaccine in preventing clinical malaria.

Dr Alonso said: "This is the first trial in which we are testing children with little immunity in a malaria endemic area."

Ripley Ballou, vice president in clinical research and development in emerging diseases at GlaxoSmithKline Biologicals, said that he was confident the vaccine would protect children but said there were still question marks.

"After a period of eight to 10 weeks the protection wanes. One of the questions we still don’t understand is how long the protection will last in the paediatric setting. There is no protection data in paediatrics," he said.

"The children have no immunity, unlike the Gambian adults. There’s a different population and a different end point—not whether they become infected but whether they develop clinical malaria," he said.

A spokeswoman for the Malaria Vaccine Initiative said: "We hope that the vaccine will be effective for longer in children. Their immune systems are different from the immune systems of adults. The project team is constantly looking for ways to improve the vaccine. We have no interest in deploying a vaccine which only works for a couple of months."

Professor Adrian Hill, Wellcome Trust principal research fellow at the Institute of Molecular Medicine at Oxford University, predicted that a malaria vaccine could be on the shelves within the next five to eight years.

He said: "A malaria vaccine is possible. It needs a huge amount more in resources and time. At least three vaccines are showing some efficacy."

Melinda Moree, director of the Malaria Vaccine Initiative, called for a global effort to eradicate the disease, which kills one million people every year.

"Malaria is not just a nuisance disease in Africa—it’s a huge killer of young children. We need to destroy the idea that malaria is something we can live with; it is something that is unacceptable," she said.