Long-term (5-year) antibody persistence following two- and three-dose regimens of a combined hepatitis A and B vaccine in children aged 1-11 years

This study compared the long-term persistence of anti-hepatitis A (anti-HAV) and B (anti-HBs) antibodies, 5 years after vaccination of subjects aged 1-11 years with a combined hepatitis A and B vaccine either in a two-dose (0, 6 months, Adult formulation) or a three-dose (0, 1, 6 months, Paediatric formulation) schedule. At the end of the 5 years, all subjects (100%) in both groups continued to have anti-HAV antibodies > or =15mIU/mL, while 94-97% of subjects in both groups had anti-HBs antibody concentrations > or =10mIU/mL. Subjects with anti-HBs antibody concentration < or =10mIU/mL were administered a challenge dose of hepatitis B vaccine. All subjects mounted a vigorous immune response to the challenge indicating the presence of immunological memory to HBV.Helen Marshall, Terry Nolan, Javier Díez Domingo, Lars Rombo, Etienne M. Sokal, Josep Marès, Josep M. Casanovas, Sherine Kuriyakose, Maarten Leyssen and Jeanne-Marie Jacque