In malaria endemic areas, red cell polymorphisms that confer protection against acute uncomplicated malaria, severe malaria, and malaria mortality are widespread. However, the mode of selection favouring the red cell disorders and the precise mechanism of malaria protection remains unknown. In this book, the authors describe possible mechanisms by which the red cell disorders might confer resistance or susceptibility to human Plasmodium. This book shows how the interactions between Plasmodium species appear more evident through natural host protection or susceptibility and offer a good opportunity to better knowledge on this subject poorly understood. The authors have evaluated the consequences in vaccines development.