By Maggie Fox
An experimental malaria vaccine produced by GlaxoSmithKline is the most promising yet, protecting up to 65 percent of infants from infection in two studies conducted in Africa, researchers reported.
Separate tests in Kenya and Tanzania showed GlaxoSmithKline's vaccine called RTS,S could protect babies and toddlers from infection with malaria and could prevent disease even in those already infected.
While the vaccine is far from perfect, it is the best yet against the mosquito-borne parasite, the researchers agreed. They said they would now begin the last clinical trial stage before seeking regulatory approval next year.
"Even a partially effective vaccine has the potential to save hundreds of thousands of lives each year," said Christian Loucq, director of the nonprofit PATH Malaria Vaccine Initiative, which helped to conduct the study.
"We are one important step closer to the date when malaria will join diseases such as smallpox and polio, which have been either eliminated or controlled through vaccines," Loucq said.
The World Health Organisation estimates malaria killed 881 000 people and infected 247 million worldwide in 2006. Some malaria experts say those numbers underestimate the problem.
The disease is especially hard to fight as people are continually infected by mosquitoes throughout their lives. The tiny parasites pass from the mosquitoes into the blood and live and reproduce inside the body, causing fever and sometimes deadly brain infections.
Dr. Salim Abdulla of the Bagamoyo Research and Training Centre in Tanzania and colleagues tested 340 infants, giving them three doses of the RTS,S vaccine or three doses of hepatitis B vaccine.
The malaria vaccine protected 65 percent of infants from infection with malaria during the six months of the trial.
"We are very confident that the efficacy of the vaccine extends for several years," Joe Cohen of GlaxoSmithKline Biologicals in Belgium told the briefing.
An earlier study had shown the vaccine could protect children for at least 18 months.
The children also got vaccines against diphtheria, tetanus, whooping cough and Haemophilus influenza B as part of a World Health Organisation childhood vaccination program and the vaccines all worked well, the study showed.
In a second trial, Dr. Ally Olutu of the KEMRI-Wellcome Trust Collaborative Research Centre in Kenya and colleagues vaccinated 894 children aged five to 17 months with three doses of either a slightly different formulation of the malaria vaccine or a rabies vaccine.
The found clinical episodes of malaria fell by 53 percent.
While this is different from complete protection from infection, the researchers said the point is to protect children from disease and they felt the results were comparable.