Five-year follow-up of immune response after one or two doses of inactivated hepatitis A vaccine given at 1 year of age in the Mendoza Province of Argentina

The study was conducted to further investigate the single-dose approach of hepatitis A vaccination, while providing supportive data on the flexibility of booster administration. Participants received at least one dose of Avaxim 80U Pediatric at 11-23 months of age, and they will be followed for 10 years. The report here covers the fourth and fifth years after the first vaccination .... The study finds that highest concentrations were found in the children who received 2 vaccine doses. Hepatitis A humoral immunity induced by a single dose of inactivated hepatitis A vaccine can persist for at least 5 years in a paediatric population. The study results also support recommendations in favour of a flexible time window for booster vaccination.