Immunogenicity of hepatitis B vaccine in healthy very low birth weight infants.

Abstract We studied the immunogenic response to hepatitis B vaccine of infants weighing ≤ 1500 gm at birth. Infants were divided into two groups: those weighing ≤ 1000 gm ( n = 22) and those weighing 1001 to 1501 gm ( n = 28). When immunized early (3 days of age, n = 25), these infants had a response rate (defined as antibody to hepatitis B surface antigen titer > 10 mIU/ml) of 68%, whereas when the first vaccine was given at 1 month of age ( n = 25), a 96% response rate was noted, irrespective of birth weight and weight at the time of immunization ( p