Despite decades of effort, malaria remains a global health challenge, with current vaccines offering only modest and short-lived protection. This clinical trial brings fresh hope by testing a next-generation vaccine strategy using live, genetically attenuated Plasmodium falciparum parasites.
In this double-blind, controlled study, researchers immunized malaria-naïve adults using mosquito bites carrying a late-liver-stage-arresting parasite (GA2). After three immunizations, 89% of participants in the GA2 group were protected against malaria in a controlled infection challenge—compared to just 13% in the early-arresting GA1 group and none in the placebo group.
GA2 also triggered stronger cellular immune responses, particularly in CD4+ and γδ T cells, while maintaining a similar antibody profile to GA1. These findings suggest that extended liver-stage exposure may be key to more effective, long-lasting malaria immunity.
With its strong safety profile and high efficacy, GA2 represents a promising step forward in the quest for a more powerful malaria vaccine.