IMMUNOGENICTY OF A PEDIATRIC FORMULATION OF VAQTAÔ IN KOREA
Sohn YM, Lee JS, Park JH, Park MS, LeeWS*,
Poerschke G*, Kuter B*, Evans K*;
Yonsei University, Seoul, Korea; MSD
Korea*, MSD Asia Ltd.*, Merck Research Lab., PA, USA*
Objective: To assess the immunogenicity, safety
and tolerability of VAQTAÔ [Hepatitis A [HA] vaccine, purified
inactivated, MSD] in healthy children and adolescents.
Methods: Eligible subjects ages 2 to 17 years
received 25U/0.5 mL of VAQTAÔ, IM, at 0 and 24 weeks. Serum samples
were obtained prior to dose 1 to ascertain serostatus and 4 weeks after the
2nd dose to ascertain immunogenicity of the 2-dose
series. To detect antibody response to HAV after vaccination with VAQTAÔ, a modification of the Abbot HAVABÒ kit was used.
Samples with titers ³ 10 mIU/mL were considered
seropositive. Adverse Events were
monitored for 14 days after each injection.
Results: 102 subjects [54 male, 48 female] were
enrolled. The mean age was 6.8 ¡À 3.5 years.
Two subjects were seropositive, 2 were lost to follow-up and after 2nd
dose 10 withdrew. 88 subjects were available for a per protocol analysis
and 90 for all subjects with serology. All subjects seroconverted 4
weeks after dose 2. Geometric mean titer was 7991.1 mIU/mL [95% CI 6481.1
to 9852.7) with very little difference in per protocol and all subjects
analysis. Adverse reactions to VAQTA were generally mild and transient.
Conclusions: This was the first evaluation of the CR326F strain derived hepatitis A
vaccine in Korea. The pediatric two-dose regimen of VAQTAÔ
was found to be highly immunogenic, generally well tolerated and resulted
in 100% seroconversion. Routine vaccination should be considered to
effectively control the increasing disease burden of HAV seen in Korea.