The main objective of this study is 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).

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).

Inclusion Criteria:

• Comparator group :
• Have received 3 doses of Infanrix-hexa as part of the regular vaccination program at the age of 2, 4 and 18 months.
• Study groups:
• Have received 1 dose of Infanrix-hexa as part of the regular vaccination program at the age of 2 months.

Exclusion Criteria:

• Have received other doses of hepatitis B vaccine;

• Considered immunosuppressed;

• Have an autoimmune disease;

• Have contraindications to HBV vaccination, as defined in the Quebec Immunization Protocol;

• Have a bleeding disorder;

  • Have a significant developmental delay;
  • Have or plan to participate in other clinical studies with vaccines or products not licensed in Canada;
  • Have presented a serious clinical condition to the vaccines administered as part of the study.

No individual data will be shared with any other researchers outside of this study