Efficacy of hepatitis A vaccination in children aged 12 to 24 months

Background. Current hepatitis A vaccines are either licensed for children > 2 years of age. as in the U.S. or Chile, or >1 year of age, as in Europe an d other parts of the world. Recent recommendations for immunization against hepatitis A have included routine vaccination of children in areas or regi ons of higher endemicity. However, data on hepatitis A vaccination in toddl ers aged between 1 and 2 years are scarce. Methods. This open clinical study investigated the reactogenicity and immun ogenicity of two doses (0, 6-month schedule) of an inactivated hepatitis A vaccine (Havrix((TM)) pediatric, Glaxco SmithKline Biologicals, Rixensart, Belgium) in 120 seronegative children aged 12-24 months. Results. Pain at the injection site and irritability were the most frequent ly reported local and general symptoms, respectively. No serious adverse ev ents related to the study vaccine were reported. One month after the first dose, all but one subject had antibodies against hepatitis A with a GMT of 159 mIU/mL. After the booster dose., all had antibodies with a GMT of 2,939 mIU/mL. Conclusions. Our data show that the inactivated hepatitis A vaccine was wel l tolerated by these toddlers and that the vaccine elicits a good immune re sponse. (C) 2001 IMSS. Published by Elsevier Science Inc.