Lasting immune memory against hepatitis B following challenge 10-11 years after primary vaccination with either three doses of hexavalent DTPa-HBV-IPV/Hib or monovalent hepatitis B vaccine at 3, 5 and 11-12 months of age.

•10–11 years after DTPa-HBV-IPV/Hib vaccination, 48.4% maintained anti-HBs ≥10mIU/ml.•10–11 years after DTPa-IPV/Hib+HBV vaccination, 58.4% maintained anti-HBs ≥10mIU/ml.•DTPa-HBV-IPV/Hib induced immune memory similar to monovalent HBV-primed subjects.•Duration of protection is likely similar after DTPa-HBV-IPV/Hib and monovalent HBV.•The HBV challenge dose was well tolerated and had an acceptable safety profile.