Latest vaccine trial results show a reduction in malaria by approximately one-third in African infants aged 6 to 12 weeks – lower than that seen in the older age group a year ago.

The results also showed there was no overall increase in reporting of serious adverse events in the infants vaccinated with RTS,S, demonstrating an acceptable safety and tolerability profile.

Eleven partner African research centres in seven African countries – Burkina Faso, Ghana, Gabon, Kenya, Tanzania, Malawi and Mozambique – are conducting this trial, together with GlaxoSmithKline (GSK) and the PATH Malaria Vaccine Initiative (MVI), with grant funding from the Bill & Melinda Gates Foundation to MVI.

The key results of a pivotal late-stage Phase III trial of the RTS,S malaria vaccine candidate in African infants were presented at the International African Vaccinology Conference in Cape Town, South Africa.

Malaria kills approximately 655,000 people a year worldwide and causes illness in hundreds of millions more; most of them are children under the age of five in sub-Saharan Africa.

When compared to immunization with a control vaccine, infants vaccinated with RTS,S had one-third fewer episodes of both clinical and severe malaria and had similar reactions to the injection. In this trial, RTS,S demonstrated an acceptable safety and tolerability profile.

“An effective malaria vaccine would be a welcome addition to our tool kit, and we’ve been working toward this goal with this RTS,S trial. This study indicates that RTS,S can help to protect young babies against malaria. Importantly, we observed that it provided this protection in addition to the widespread use of bed nets by the trial participants,” Dr. Salim Abdulla, a principal investigator for the trial from the Ifakara Health Institute, Tanzania.

He added that “the efficacy is lower than what we saw last year with the older 5-17 month age category, which surprised some of us scientists at the African trial sites. It makes us even more eager to gather and analyze more data from the trial to determine what factors might influence efficacy against malaria and to better understand the potential of RTS,S in our battle against this devastating disease. We were also glad to see that the study indicated that RTS,S could be administered to young infants along with standard childhood vaccines and that side effects were similar to what we would see with those vaccines.”

Follow-up in this Phase III trial will continue to provide more data for analyses to better understand the different findings between the age categories.

The final data is expected in 2014.