[Premature infants and hepatitis B vaccination. Study Group Prevention Neonatal Hepatitis B].

Since 1986 health authorities in the Netherlands advise to vaccinate preterm infants at similar age as term infants, without correction for their shortened gestational age. This advice was based on a study, which showed comparable immune responses after DTP vaccination in preterm and term infants. To assess the immunogenicity of hepatitis B vaccination not corrected for gestational age in preterm infants, we compared the antiHBs titer after hepatitis B vaccination in 44 preterm infants with the antiHBs titer in 829 term infants. More than 95% of the preterm infants developed an adequate immune response (> 10 IU/l antiHBs), irrespective the vaccination scheme which varied in vaccine dose, the number of vaccinations and the onset of the first vaccination. The percentage preterm infants with an antiHBs titer > 10 IU/l (98%) was not different of the corresponding percentage of term infants (98%). Similarly, no difference between preterm and term infants was observed when an antiHBs value of 100 IU/l was considered a positive response, neither when active immunisation started at month 0 or month 3. The geometric mean titre at 12 months of age was considered.