Researchers have reported at a malaria conference in Durban, South Africa, that the jab continues to protect a substantial proportion of babies and young children 18 months after vaccination.

The mosquito-borne disease kills around 660,000 people every year, most of them children in Sub-Saharan Africa.

British pharmaceutical firm GlaxoSmithKline (GSK), which makes the vaccine, said that it will apply for a licence from the European Medicines Agency next year.

If the vaccine - code-named RTS,S - is confirmed to be safe and effective, the World Health Organisation has indicated that it will support use of the vaccine as soon as 2015.

A South Sudanese man with his daughter, who is being treated for malaria

GSK has vowed to sell the vaccine at cost price plus 5%, which it said would fund further research into tropical diseases.

The new results are from a study of 15,000 babies and children in seven African countries.

They show the vaccine is far from perfect, but still offers significant protection.

Eighteen months after a three-dose vaccination programme, young children were 46% less likely to suffer clinical malaria.

For every 1,000 children vaccinated, 21 cases of severe malaria were prevented, according to the results.

The vaccine was less effective in babies. Infants who had the jabs when they were just a few weeks old were 27% less likely to suffer from malaria.

Scientists will now investigate whether a booster dose can increase protection in the longer term.

Halidou Tinto, one of the study's principle investigators, said the vaccine had "the potential to have a significant public health impact".

"Many millions of malaria cases fill the wards of our hospitals," Dr Tinto said.

"Progress is being made with bed nets and other measures, but we need more tools to battle this terrible disease."

British pharmaceutical company GSK makes the vaccine

GSK chief executive Sir Andrew Witty said: "While we have seen some decline in vaccine efficacy over time, the sheer number of children affected by malaria means that the number of cases of the disease the vaccine can help prevent is impressive.

"These data support our decision to submit a regulatory application for the vaccine candidate which, if successful, would bring us a step closer to having an additional tool to fight this deadly disease."

The development of the jab has been jointly funded by GSK and Bill and Melinda Gates through the PATH Malaria Vaccine Initiative.

Professor Eleanor Riley from the London School of Hygiene and Tropical Medicine said if the vaccine is cheap enough it has huge potential.

"It would be great if the vaccine had 80-90% efficacy," she told Sky News.

"But it has taken us 15 years to get this far with this vaccine.

"The question is: can we wait another 15 years before we roll out a vaccine that is going to save lives?"