Multicentre Study to Assess Persistence of Antibodies Against Hepatitis B and Immune Response to a Hepatitis B Challenge Dose in Healthy Children 7 to 9 Years Old Previously Vaccinated With 4 Doses of GSK Biologicals' DTPa-HBV-IPV/Hib Vaccine

Persistence of seroprotective antibody concentrations & immunological memory shown by the ability to mount a response to a challenge dose of HBV vaccine

血清保护性抗体浓度的持久性及免疫记忆，可通过针对乙型肝炎病毒（HBV）疫苗攻毒剂量产生应答的能力得到证实。