Background: To evaluate the safety and immunogenicity of the thiomersal-free (TF) and thiomersal-containing (TC) formulations of Hepavax-Gene(R) in healthy Vietnamese neonates.
Methods: A single-blind, randomized, controlled study in Ho Chi Minh City, Vietnam. Healthy infants, born after a normal gestational period (37 to 42 weeks) to HBsAg-negative mothers participated in the study. Subjects were randomly allocated in a 1:1 ratio to receive either Hepavax-Gene(R) TC or Hepavax-Gene(R) TF using a standard 0-1-6 month administration schedule. Post-vaccination blood samples were taken at Months 1, 6 and 7. Parents/legal guardians recorded solicited local and systemic adverse events up to four weeks after each vaccination.
Results: Very high proportions of subjects were seroprotected. Seroprotection rates at 1, 6 and 7 months were all above 95% using a 10 IU/L cut-off, and were mostly above 90% using a 100 IUI/L cut-off. Seroprotection rates between the two formulations were equivalent within a 5% margin for either cut-off titer both after 6 and 7 months.
There were no significant differences in the numbers adverse events reported between the two formulations. Safety results were in line with previous reports for Hepavax-Gene(R). Both formulations of Hepavax-Gene(R) were well tolerated. There were no local adverse events reported in the TF group. No SAEs were reported during the study.
Conclusions: The thiomersal-free formulation of Hepavax-Gene(R) was non-inferior to the thiomersal-containing formulation of Hepavax-Gene(R) in terms of immunogenicity. There was evidence that the thiomersal-free vaccine was associated with fewer local adverse events.
(C) 2014 by Lippincott Williams & Wilkins, Inc.