Dismay at the effectiveness of GSK’s malaria vaccine

The expectations and anticipation regarding the world’s first potential malaria vaccine have been dealt a blow after trial results demonstrated that the protection the vaccine offers, can significantly diminish and disappear altogether over time, disappointing researchers who had high hopes for it.

Developed by British pharmaceutical giant GlaxoSmithKline (GSK), the new vaccine is currently only referred to as ‘RTS,S’. Scientists state that full data from final-stage trials which include 15,000 children, are expected by the end of 2014. However, early results from the vaccine are not encouraging and expose the difficulties in creating a vaccine that offers full protection from a deadly disease such as malaria that claims the lives of more than 650,000 children every year – the most ‘at risk’ group in regards to mosquito bites.

The vaccine has been primarily engineered to help babies aged between six to 12 weeks and in a large-scale phase III trial that was carried out last year, only a third of babies aged within this range were prevented from becoming ill after being administered the new vaccine. Moreover, the protection was lower than what was evident in older children.

Microsoft co-founder Bill Gates, worth an estimated £40bn, was one of the backers behind the research, and after those results emerged last year he commented: “The efficacy came back lower than we had hoped, but developing a vaccine against a parasite is a very hard thing to do.”

Christopher Plowe, a malaria researcher at the University of Maryland School of Medicine in the United States, who was not involved in the RTS,S trial, also spoke on the findings last year, saying: “The results are kind of disappointing because we’d all like to see a malaria vaccine that has closer to 80 percent or 100 percent efficacy.”

Results of the latest data were published this week in the New England Journal of Medicine. Although the RTS,S vaccine was found to have a rate of protecting peaking at 53%, after an average of merely eight months, the level of protection had declined at an alarming rate.

Ally Olotu of the Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme in Kenya, who led the follow-up study, said: “It was a bit surprising to see the efficacy waned so significantly over time. In the fourth year, the vaccine did not show any protection.”

A GSK spokesperson commented on the latest results, stating that because they were derived from a small, mid-stage trial, they did not “provide definitive answers about the duration of protection or how the vaccine candidate works in different malaria transmission settings.”

Phillip Bejon, a researcher at the KEMRI-Wellcome Trust programme, was involved with the study and he said in spite of the decreasing effectiveness, “there is still a clear benefit to the vaccine.”

Bejon added: “Many of the children (in Africa) will experience multiple episodes of clinical malaria infection, but overall we found that 65 cases of malaria were averted over the four-year period for every 100 children vaccinated. We now need to look at whether offering a vaccine booster can sustain efficacy for longer.”