The effects of booster vaccination on combined hepatitis A and hepatitis B vaccine in both anti-HBs and anti-HAV negative children 5–15 y after hepatitis B vaccine primary immunization

In the present study, we investigated the changes in both anti-HAV lgG and anti-HBs lgG levels and compared the antibody seroconversion rates of different doses of combined hepatitis A and hepatitis B vaccine in children. Children who were vaccinated as infants with Hepatitis B vaccine were revaccinated at 5–15 y of age, then the antibody titers were monitored. Among 283 children, this study found that the anti-HAV seroconversion rates (defined as anti-HAV ≥ 1mIU/ml) after the first and the third dose were 79.9% and 100% respectively; these observed differences were statistically significant (P 0.05). This study demonstrated that the immunization effects of booster vaccination with combined hepatitis A and hepatitis B vaccine is successful for children. A single booster dose is adequate for younger children, while three doses are needed for older children.