[Efficacy and tolerance of vaccinations in premature infants].

Immunization may prevent an enhanced risk of infectious diseases, providing that it is completed on time. A review of the literature summarizes several studies on effectiveness, safety and duration of protection in preterm infants. Immune maturation depends on chronological age rather than gestational age. Then immunization against diphteria-tetanus-pertussis-poliomyelitis-Haemophilus influenzae b should be initiated at 2 months of age and completed prior than 6 months. The youngest preterm infants, still hospitalized at 8 weeks of age should be monitored following the first immunization as they may develop apnea episodes, probably linked with the pertussis component of the vaccine. In premature, BCG vaccination induces a delayed hypersensitivity to tuberculin less important than in full-term neonates, and should not be given right after birth in newborns less than 33 weeks of gestational age. Hepatitis B vaccination should be offered as soon as two months of age and even at birth to children born from HBs Ag carriers. Neither duration of immunity, nor safety are modified by prematurity.