Reappraisal of the Immunogenicity and Safety of Three Hepatitis A Vaccines in Adolescents

Abstract

Although the overall incidence of hepatitis A in Korea has been decreasing, adolescents remain highly vulnerable to its outbreaks. This study was conducted to compare the immunogenicity and safety of three hepatitis A vaccines in Korean adolescents. Healthy anti-hepatitis A virus seronegative subjects aged 13 to 19 yr were randomized in three equal groups to receive two doses of Avaxim (TM), Epaxal (R), or Havrix (R), 6 to 12 months apart. Seroconversion rates one month after the first dose were 98%, 95%, and 93% for Avaxim (TM), Epaxal (R), and Havrix (R), respectively. Seroconversion rates reached 100% for all vaccine groups one month after the second dose. Anti-HAV geometric mean concentrations (GMCs) were 7,207.7 mIU/mL (95% CI, 6023.1-8684.7), 1,750.5 mIU/mL (95% CI, 1362.9-2248.3), and 1,953.5 mIU/mL (95% CI, 1459.4-2614.7) after two doses of Avaxim (TM), Epaxal (R), and Havrix (R) respectively. Avaxim (TM) was significantly more immunogenic than Epaxal (R) and Havrix (R), whereas there were no significant differences in antibody responses between Epaxal (R) and Havrix (R). Local and systemic solicited adverse events (AEs) were mostly of mild-to-moderate intensity and resolved within 5 days. No serious AEs were reported. In conclusion, all three vaccines are highly immunogenic and well-tolerated in Korean adolescents.