In the province of Quebec, Canada, hepatitis B vaccination of infants involves three doses of vaccine, 2, 4 and 18 months of age. However, in the current epidemiological context (virtual absence of new cases in young Quebecers) and taking into account scientific data which consistently show a high immunogenicity and efficacy of two doses of hepatitis B vaccine, the relevance of the second dose given at the age of 4 months is questionable.

this study is designed to compare the immunogenicity of the hepatitis B component in children vaccinated with (I) two doses of Infanrix-hexa administered at 2 and 12 months of age versus (II) one dose of Infanrix-hexa and one dose of Twinrix administered respectively at 2 and 12 months of age versus (III) three doses of Infanrix-hexa administered at 2, 4 and 18 months of age (comparator).