LONDON (AFP) - European regulators on Friday gave the go-ahead for the world's most advanced malaria candidate vaccine, despite mixed results from a years-long trial on nearly 15,500 children in seven African countries.
The London-based European Medicines Agency (EMA) said in a statement it had adopted "a positive scientific opinion for Mosquirix... for use outside the European Union". The drug is also known as RTS,S.
The vaccine is aimed at young children -- the main victims of malaria -- and is being developed by the British pharmaceutical giant GlaxoSmithKline (GSK).
"The CHMP (Committee for Medicinal Products for Human Use) concluded that despite its limited efficacy, the benefits of Mosquirix outweigh the risks," the EMA said.
"After decades of research into malaria vaccinations, Mosquirix is the first vaccine for the disease to be assessed by a regulatory agency," it added.
The World Health Organization is evaluating the vaccine "as an addition to" existing treatments, and not as a substitute, the WHO says on its website.
The vaccine, aimed at children aged between six weeks and 17 months, has been developed with backing from non-profit group PATH Malaria Vaccine Initiative and the Bill and Melinda Gates Foundation.
The mosquito-borne disease kills some 584,000 people per year -- more than 75 per cent of them children under five, according to the WHO.
"This is a hugely significant moment. I've been working on this vaccine for 30 years and this is a dream come true," GSK's head of research, Ripley Ballou, was quoted by the BBC as saying.
- Most clinically-advanced vaccine -
The final results of a trial with RTS,S were published in The Lancet earlier this year, showing it offers partial protection for young children that wanes over time.
In spite of the drug's partial effect, it remains the most clinically-advanced vaccine against malaria, which kills about 1,200 children in sub-Saharan Africa on average per day.
The trial administered the vaccines to two groups of children -- the first aged five to 17 months and the other six to 12 weeks.
Compared to children not given the vaccine, those in the older age group enjoyed a protection rate of about 50 per cent in the first year against clinical or non-life threatening malaria -- dropping to 28 per cent after four years, said the study.
A booster shot given 18 months later increased the protection rate at year four to 36 per cent.
The comparable figures for the younger group were 18 per cent after three years, and 26 per cent with the booster.
For severe malaria, those in the older group who received an extra shot enjoyed a protection rate of 32 per cent after four years, but without a booster the vaccine offered no noticeable defence.
The trial did not answer the question of how often a booster would be needed, or how many times it would be safe to administer one.
The killer parasite has developed resistance to successive treatments, and insecticide-treated bed nets remain one of the most effective prevention methods.