Immunogenicity of hepatitis B vaccine in preterm infants

Aim-To assess the immunogenicity of hepatitis B vaccine in preterm and term infants, given in a sequence of three doses beginning soon after birth. Method-The immunogenicity of hepatitis B vaccine was assessed in 176 preterm infants (< 35 weeks of gestation), immunised soon after birth, and compared with that in 46 term infants. Titres of hepatitis B antibodies were determined one to two months after the third vaccine. The significance of the differences between the term and preterm groups was determined using Student's t test. Results-A similar proportion of infants in both preterm and term. groups attained protective titres of hepatitis B antibodies (88.7% vs 93.4%, respectively; p=NS). However, the term infants had a higher geometric mean titre of antibodies after the third vaccine than did the preterm infants (701.2 (745.0) vs 469.1 (486.2) mU/ml, respectively; p<0.03). Conclusion-Hepatitis B vaccine is effective in most preterm infants when given soon after birth. It may be advisable to determine the immune response at 12-24 months of age to booster the non-responders.