Some vaccination-protected children developed chronic HBV infection in adulthood. Vaccination-protected children have increased risk when born to HBsAg(+) mothers. More anti-HBc(+) vaccinated children develop HBsAg(+) when born to HBsAg(+) mothers. Vaccinated children born to HBsAg(+) mothers benefit from adolescent booster. Adolescent booster might be appropriate for anti-HBs(−) high-risk individuals.