Introduction
Introduction
Global eradication of smallpox and the forthcoming eradication of poliomyelitis are testimony to the power of immunization programs. It is both notable and sobering that over 2,000,000 newborns and infants under 6 months of age die each year due to infections. Substantial morbidity and mortality among neonates and infants is related to vaccine-preventable infectious diseases. Immunization of pregnant mothers and passive transmission of antibodies to the fetus may be an effective way to protect the neonate, but is limited by substantial safety and medico-legal concerns. Neonatal immunization is an approach that combines 2 major advantages: (a) birth is the most frequent and consistent point of healthcare contact, and (b) it initiates early protective responses that shield the susceptible infant. Thus neonatal vaccines achieve relatively high population penetration.