Persistence of antibody and immunologic memory in children immunized with hepatitis B vaccine at birth

Forty-two healthy children immunized with a course of hepatitis B vaccine beginning at birth were tested at 6 years of age for persistence of anti-hepatitis B antibody (anti-HBs) and then given a booster dose of vaccine. Although nearly one-half had become seronegative, all retained robust immunologic memory and rapidly regained a protective anti-HBs titer of at least 10 mIU/ml after booster vaccination.