Abstract
We review the current knowledge regarding how best to approach development of lasting immunity in infancy without inducing unwanted adverse vaccine effects among which could be sudden infant death syndrome and neurological developmental problems. The review also addresses current problems in vaccine development generally including formulating infant vaccination schedules based on knowledge obtained in trials conducted in adults, a process so fundamentally flawed to warrant intense review. We explain the two key mechanisms by which the infant and adult human protects itself from foreign pathogens these being the very complex but integrated immune systems – the Th1-based Mucosal Immune System and the Th2-based Systemic Immune System. The potential issue of hyperimmunization is discussed and the review addresses the latest developments that could provide a useful path to safer immunisation in infancy.