Immune response to hepatitis B vaccine in premature neonates.

The immunogenecity of a recombinant yeast-derived hepatitis B vaccine in 25 premature infants who were born to HBsAg negative mothers was studied. The gestational ages were 28-37 weeks and birth weights were 1300-2000 grams. Seroconversion occurred in 22 infants, the anti HBs titers varied between 50 and 13,470 IU/L (Geometric mean titer = 542 IU/L).