Medical Correspondent, BBC News
Scientists and global health campaigners have welcomed the early results of a malaria vaccine trial in African infants.
Malaria is spread by mosquitoes
Tests showed the vaccine gave a high level of protection, and was safe
The results, published online by the Lancet, appear to bring closer the prospect of a vaccine against one of the developing world's biggest killers.
Every 30 seconds a child in Africa dies from malaria - around one million every year.
So an effective vaccine would have massive life-saving potential.
A prototype vaccine has been in development and trials for 20 years and now it has been tested in African babies - the most vulnerable of all age groups.
The study, was small, involving 214 infants in Mozambique. Furthermore, these are early results, so caution is needed in interpreting the data.
But crucially the vaccine was shown to be safe.
But it also appears highly protective: after three months infants who'd received it were 65% less likely to contract malaria than a control group.
The quest for a vaccine represents a partnership between several African nations, the pharmaceutical industry and the PATH Malaria Vaccine Initiative (MVI).
Christian Loucq, director of MVI, said: "These results essentially provide another green light indicating that we can move toward a large Phase 3 trial with this vaccine."
That trial will begin next year in ten sites across sub-Saharan Africa and involve 10,000 children.
If successful the vaccine will be licensed in 2011.
It would mark a hugely significant step forward in the fight against malaria.
Dr Joe Cohen, from GlaxoSmithKline, has spent 20 years on the project.
He said: "Creating a malaria vaccine has been a huge challenge because of the complexity of the disease.
"We have plenty of vaccines against viruses and bacteria but this would be the first vaccine against a parasitic infection in humans."
The Microsoft billionaire Bill Gates has given hundreds of millions of dollars to malaria vaccine and treatment programmes.
He called on global leaders to embrace "an audacious goal - to reach a day when no human being has malaria, and no mosquito on earth is carrying it."
He was speaking in Seattle to a meeting of 300 scientists and policymakers.
"We have a real chance to build the partnerships, generate the political will, and develop the scientific breakthroughs we need to end this disease," he said.
"We will not stop working until malaria is eradicated."