Antibody titres after primary and booster vaccination of infants and young children with a virosomal hepatitis A vaccine (Epaxal).

To evaluate the immunogenicity and tolerability of Epaxal in infants and children, 30 infants (aged 6-7 months) and 30 children (aged 5-7 years) received a single intramuscular dose of the aluminium-free virosomal hepatitis A virus (HAV) vaccine Epaxal and a booster dose after 12 months. Anti-HAV antibody titres were measured at baseline (before injection), at 1 and 12 months after primary vaccination, and 1 month after the booster vaccination. Sixteen evaluable infants had maternal anti-HAV antibodies at baseline. Complete seroprotection (titre >/= 20 mIU/ml) was achieved by all infants and children at Month 1 and at Month 12. Additionally, all subjects showed a strong antibody response to booster vaccination. In infants without maternal anti-HAV antibodies, the response was four-fold higher than in those with maternal anti-HAV antibodies. Both doses of Epaxal were well tolerated. These preliminary data suggest that Epaxal is an effective hepatitis A vaccine for children and infants from 6 months of age.