(4) children 15 to 18 months of age who received INFANRIX coadministered with Hib conjugate vaccine (PRP-T) at month 0 and HAVRIX at months 1 and 7;

(5) children 23 to 25 months of age who received HAVRIX on a 0- and 6-month schedule.

The anti-hepatitis A antibody vaccine responses and geometric mean antibody titers (GMTs), calculated on responders for groups 1, 2, and 5 are presented in Table 1. Vaccine response rates were similar among the three age groups that received HAVRIX. One month after the second dose of HAVRIX, the GMT in each of the younger age groups (11 to 13 and 15 to 18 months of age) was shown to be similar to that achieved in the 23 to 25 months of age group.

Table 1. Anti-hepatitis A Immune Response Following Two Doses of HAVRIX
720 EL.U./0.5 mL Administered 6 Months Apart in Children Given the First Dose of
HAVRIX at 11 to 13 Months of Age, 15 to 18 Months of Age, or 23 to 25 Months of Age

Vaccine response = Seroconversion in children initially seronegative or at least the maintenance of the pre-vaccination anti-HAV concentration in initially seropositive children.

GMT = Geometric mean antibody titer.

*Calculated on vaccine responders one month post-dose 2. GMTs in children 11 to 13 months of age and 15 to 18 months of age were non-inferior (similar) to the GMT in children 23 to 25 months of age (i.e., the lower limit of the two-sided 95% CI on the GMT ratio for Group 1/Group 5 and for Group 2/Group 5 were both ≥0.5).

Immunogenicity in Children and Adolescents: Immune Response to HAVRIX 360 EL.U. in Children Vaccinated Beginning at 2 Years of Age: In 6 clinical studies of subjects 2 to 18 years of age (n = 762) who received 2 doses of HAVRIX (360 EL.U.) given 1 month apart, the GMT ranged from 197 to 660 mIU/mL. Ninety-nine percent of subjects seroconverted following 2 doses. When a booster (third) dose of HAVRIX 360 EL.U. was administered 6 months following the initial dose, all subjects were seropositive 1 month following the booster dose, with GMTs rising to a range of 3,388 to 4,643 mIU/mL. In 1 study in which children were followed for an additional 6 months, all subjects remained seropositive. Solicited adverse effects were similar in frequency and nature to those seen following administration of ENGERIX-B® [Hepatitis B Vaccine (Recombinant)].

Immune Response to HAVRIX 720 EL.U./0.5 mL in Children Vaccinated Beginning at 2 Years of Age: In 4 clinical studies, children and adolescents (n = 314), ranging from 2 to 19 years of age, were immunized with 2 doses of HAVRIX 720 EL.U./0.5 mL given 6 months apart. One month after the first dose, seroconversion ranged from 96.8% to 100%, with GMTs of 194 mIU/mL to 305 mIU/mL. In studies in which sera were obtained 2 weeks following the initial dose, seroconversion ranged from 91.6% to 96.1%. One month following a booster dose at month 6, all subjects were seropositive, with GMTs ranging from 2,495 mIU/mL to 3,644 mIU/mL.⁵

In 1 additional study in which the booster dose was delayed until 1 year following the initial dose, 95.2% of the subjects were seropositive just prior to administration of the booster dose. One month later, all subjects were seropositive, with a GMT of 2,657 mIU/mL.5

Also, HAVRIX has been found to be highly efficacious in a clinical study of children at high risk of HAV infection (see Protective Efficacy, above).

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