The development pathway of the most advanced candidate vaccine against malaria, RTS,S

Malaria has afflicted humans for aeons, being responsible for more deaths throughout history than any other disease. Today, infection with protozoan parasites of the genus Plasmodium still claims the lives of at least one million people each year, mainly children, in addition to the significant debilitation it causes to hundreds of millions more. Consequently, malaria has a drastic socioeconomic impact on endemic countries and therefore it has been the focus of global health initiatives for decades. Early attempts to eradicate malaria through targeting the mosquito vector failed; however, increased investment in existing control measures, such as the use of insecticide-impregnated bed nets, has been matched by renewed efforts to develop an efficacious vaccine. Sequencing of the genome of P. falciparum, which causes the most severe form of the disease, has improved knowledge of the malaria parasite‘s complex lifecycle, which, combined with a greater understanding of the human immune response to infection, has produced a number of novel candidate vaccines over the last two decades. Most notable among these is RTS,S which has shown much promise throughout a long development process, recently becoming the first candidate vaccine against human malaria to progress into phase III clinical trials. There is optimism, therefore, that in the foreseeable future RTS,S may become the first licensed antimalarial vaccine. Nevertheless, there are unresolved issues surrounding the lack of understanding of its mechanism of protection and doubt cast over its therapeutic potential. While the future success of RTS,S as a commercially available product is not certain, it is still likely to play a significant role in our ongoing fight against malaria, if only as a forerunner to a more refined second generation vaccine.