Hepatitis B immunization has been offered to all grade 4 students (age 9-10) in the province of Quebec, using Engerix-B at a dose of 10 mkg. The peak incidence of hepatitis B occurs between age 15 and 35; the proportion of vaccinated children who will still be protected at this age is currently unknown. This study is designed to determine: * persistence of immunity until age 25 * persistence of immunological memory as demonstrated by an anamnestic response following a booster dose * the effect of a booster dose on immunogenicity at either 5, 10 or 15 years after the primary vaccination course (at age (15, 20 or 25).
Three doses of Engerix-B vaccine (10 mkg) were administered according to 0, 1, 6 month schedule to 1126 9-10 year-old children. The primary objective of the study is to evaluate the persistence of antibodies to Engerix-B in all subjects at age 25 and to compare the levels obtained in those given a booster injection at age 15 or 20 with those receiving no booster injection. Secondary objectives * To determine the antibody levels obtained following primary vaccination and the proportion of children who seroconvert * To determine the antibody levels of one third of subjects at age 15, 5 years after primary vaccination (Group A) * To determine the effect on antibody levels of a booster injection at age 15 years given to one third of the subjects (Group A) * To determine the antibody levels of subjects in groups A and B at age 20, 5 years after booster (Group A), 10 years after primary vaccination (Group B) * To determine the effect on antibody levels of a booster injection at age 20 years given to one third of the subjects (Group B) * To determine the effect on antibody levels of a booster injection at age 25 years given to one third of the subjects (Group C) * To determine the antibody levels of subjects in Group A and Group B one year after their 5 or 10 year booster * To evaluate safety
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
1,129
10 mkg per dose; 3 doses according to 0, 1, 6 month schedule; booster doses 5, 10 or 15 years post-primary vaccination.
Vladimir Gilca
Québec, Quebec, Canada
To evaluate the persistence of antibodies to Engerix-B in all subjects at age 25 and to compare the levels obtained in those given a booster injection at age 15 or 20 with those receiving no booster injection.
Long term persistence of anti-HBs and the effect of a booster dose given 5, 10 or 15 years post-primary vaccination.
Time frame: 1995 - 2011
- To determine the antibody levels obtained following primary vaccination and the proportion of children who seroconvert
Anti-HBs titers were measured 1 months post-primary vaccination
Time frame: 1 month post primary vaccination
- To determine the antibody levels of one third of subjects at age 15, 5 years after primary vaccination (Group A)
Anti-HBs titers were measured 5 years post primary vaccination.
Time frame: 2001
- To determine the effect on antibody levels of a booster injection at age 15 years given to one third of the subjects (Group A)
The effect of a booster dose was measured
Time frame: 2001
- To determine the antibody levels of subjects in groups A and B at age 20, 5 years after booster (Group A), 10 years after primary vaccination (Group B)
Anti-HBs titers were measured 10 years post primary vaccination (Group B) and 5 years post booster dose (Group A)
Time frame: 2006
- To determine the effect on antibody levels of a booster injection at age 20 years given to one third of the subjects (Group B)
Anti-HBs titers were measured 1 month post booster dose given 10 years post-primary vaccination
Time frame: 2006
- To determine the persistence of antibody 15 years after primary vaccination (Group C)
Anti-HBs titers will be measured
Time frame: 2011
- To determine the antibody levels of subjects in Group A and Group B one year after their 5 or 10 year booster
anti-HBs titers will be measured 10 years post booster dose (Group A) and 5 years post booster dose (Group B)
Time frame: 2011
- To evaluate the effect of a booster dose given 15 years post primary vaccination (Group C)
Anti-HBs titers will be measured one month post booster dose (Group C)
Time frame: 2011
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