Methods: Infants were randomized to one of three groups, each receiving two doses of 720 EL.U. of hepatitis A vaccine (HAVRIX, Glaxo SmithKline) according to the following schedules: Group 1 at ages 6 and 12 months; Group 2 at ages 12 and 18 months; Group 3 at ages 15 and 21 months. We determined antibody to HAV (anti-HAV) status of mothers at the time of delivery, and measured infants' anti-HAV concentrations at the time of the first vaccine dose (baseline), and at 1, 7 and 12 months thereafter. Anti-HAV concentrations > 33 milli-International Units/milliliter (mIU/mL) were considered protective. We monitored adverse reactions using diary cards and chart reviews.