The path from early- to late-liver stage arresting genetically attenuated parasites as a malaria vaccination strategy

Genetically attenuated parasites (GAPs) that arrest during liver stage development have shown significant potential as malaria vaccines. Compared to Plasmodium falciparum GAPs that arrest after 24-48 h (early-arresters), parasites arresting after 6-7 days (late-arresters) have shown superior efficacy, highlighting the importance of liver stage immunity in promoting sterile protection. Here, we describe GAPs tested in humans and the pre-clinical research that led to their creation. We discuss safety and efficacy of existing GAPs with particular focus on their large-scale implementation as malaria vaccines.