A new experimental vaccine developed by scientists in the US attacks the malaria parasite in its early stages and could help prevent the disease that has kills one million people a year.
The new vaccine -- called RTS, S and developed by Walter Reed Army Institute of Research -- reduced the number of clinical malaria episodes by 26 percent for up to 18 months after vaccination among children in Mozambique, where malaria is common, reported the science portal EurekAlert.
There were 58 percent fewer severe episodes among the children over the same time period. The vaccine also reduced the number of clinical malaria episodes in partially immune men in Gambia by 63 percent after they received a booster shot a year later, it said.
The Cochrane Collaboration, an organisation that reviews clinical trials of the vaccine, found that it protected 41 percent of volunteers in the US who were exposed to malarial mosquitoes in the lab.
The RTS, S vaccine showed extremely promising results, the researchers said. The review appears in the latest issue of The Cochrane Library, a publication of The Cochrane Collaboration.
Malaria is a parasite carried by mosquitoes and kills at least a million people a year, especially children in Africa. It increasingly resists anti-malarial drugs, according to a report in the online edition of New Scientist.
Efforts to develop a vaccine have been frustrated because the parasite changes its form several times during an infection.
These changes alter the surface chemicals that vaccines normally exploit to prime the immune system to recognise a pathogen. Scientists are divided over which stage to vaccinate against.