The introduction of a vaccine against malaria could be less than two years away following a trial by a British healthcare company.
The results of the trial by GlaxoSmithKline (GSK) demonstrated that the most clinically advanced malaria vaccine candidate - RTS,S - continued to protect young children and infants from clinical malaria up to 18 months after vaccination.
Over a year and a half, the RTS,S vaccine was shown to almost halve the number of malaria cases in children aged five to 17 months at first vaccination.
The study of more than 15,000 infants and young children found the vaccine reduced by around a quarter the malaria cases in infants aged six to 12 weeks at first vaccination.
GSK intends to submit a regulatory application to the European Medicines Agency (EMA) next year.
The World Health Organisation (WHO) has indicated that a policy recommendation for the RTS,S vaccine candidate is possible as early as 2015 if it is granted a positive scientific opinion by the EMA.
Malaria is a significant public health burden, claiming 660,000 lives a year - mostly children in sub-Saharan Africa.
Eleven research centres in seven African countries are conducting the trial, together with GSK and the PATH Malaria Vaccine Initiative (MVI), with grant funding from the Bill & Melinda Gates Foundation to MVI.
RTS,S continued to display an acceptable safety and tolerability profile during the 18 month follow-up.
Apart from a meningitis signal previously reported, no other safety signal was identified and the occurrence of meningitis will be followed closely during the remainder of the trial.
Sir Andrew Witty, chief executive of GSK, said: "We're very encouraged by these latest results, which show that RTS,S continued to provide meaningful protection over 18 months to babies and young children across different regions of Africa.
"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. We are grateful to the scientists across Africa and GSK and to our partners who have worked tirelessly for almost 30 years to bring us to this point."
Dr David C Kaslow, vice president of product development at PATH, said: "Given the huge disease burden of malaria among African children, we cannot ignore what these latest results tell us about the potential for RTS,S to have a measurable and significant impact on the health of millions of young children in Africa.
"While we want to be careful about not getting ahead of the data, this trial continues to show that a malaria vaccine could potentially bring an important additional benefit beyond that provided by the tools already in use."
The results of the trial were published in Durban, South Africa.