Early immunization with conjugate vaccines

Conjugate vaccines have been used during the neonatal period or in early infancy in order to test their safety and immunologic behaviour. Adverse events even in neonates and premature babies have been mild and spontaneously resolving. Anticapsular antibody concentrations after first doses of Hib conjugates in early infancy are generally low, but analysis of responses clearly demonstrates active antibody production. Concentrations after the whole primary series are at or close to the level achieved in routine vaccination programmes. Noteworthy, immunologic memory seems to be induced already by first doses during newborn period. These data suggest that protection against invasive Hib infections may be achieved early in life.