Hepatitis B Immunization in Premature Infants

Source: Belloni C, et al. Immunogenicity of hepatitis B vaccine in term and preterm infants. Acta Paediatr 1998; 87:336-338.

The current aap red book states that "the optimal time to initiate hepatitis B immunization in premature infants who weigh less than 2 kg at birth has not been determined.1 Seroconversion rates in low birth weight infants, in whom vaccination was initiated shortly after birth, have been reported in some studies to be lower than those in preterm infants vaccinated at an older age or in term infants vaccinated shortly after birth."

Belloni and associates from the Division of Neonatal Intensive Care in Pavia, Italy, vaccinated 2009 neonates born of mothers negative for hepatitis B surface antigen (HBsAg).1 Ten mcg of recombinant HpB vaccine was injected intramuscularly on the fourth day of life and repeated at 1 and 6 months of age. A blood sample was taken from each infant, one month after the third dose of hepatitis B vaccine (HBV). The anti-HBs antibody serum concentration was measured by enzyme-linked immunosorbent assay (ELISA).

The response to HpB vaccine was compared in 241 preterm (gestational age < 38 weeks) and 1727 term neonates. No statistical difference was observed in the distribution of anti-HBs antibody level, either between preterm and term gestation infants, or between low birth weight (< 2500 g) and normal weight infants. Eighty-four percent of term babies had anti-HBs Ag titers greater than 100; 80% of low (1500-2499 g), very low (1000-1499 g) and extremely low (< 1000 g) birth weights had titers of greater than 100. These are statistically the same values.

The authors state that their results indicate preterm and low birth weight infants respond to HBV in the same measure as normal term infants and do not require a delay in beginning immunization with HBV. It will be interesting to see whether this study will influence the recommendations for HBV in the 2000 Red Book. -rhb

Reference

    1. AAP Committee on Infectious Diseases. 1997 Red Book. AAP, Elk Grove, IL; l997:254-255.