A step forward for an attenuated blood-stage malaria vaccine

Efforts to develop an effective malaria vaccine have encountered multiple challenges, and have had limited success to date. As the need remains urgent, novel approaches must be explored. One concept that has gained attention uses whole malaria parasites. Building on preclinical studies in animal models, Stanisic et al. describe the development of a vaccine based on chemically attenuated Plasmodium falciparum blood-stage parasites, with an evaluation of safety and immunogenicity in malaria-naïve human subjects. The vaccine was shown to be safe, well tolerated, and capable of priming antigen-specific T cells. This work, and the completion of an initial clinical trial in human subjects, represents a significant advance. While the path forward for this attenuated vaccine remains challenging, these initial findings are encouraging. Importantly, the results provide the foundation and framework for testing modified immunization protocols, and designing subsequent clinical trials to further evaluate safety, test for enhanced immunogenicity, and ultimately measure protective efficacy.