Hepatitis A vaccine immune response 22 years after vaccination.

In the United States, the incidence of hepatitis A virus (HAV) infection has been reduced through universal childhood vaccination. However, the duration of immunogenicity for the hepatitis A vaccine is not known. We report on the 22 year follow-up time point of a cohort of Alaska children who were randomized to three different vaccine schedules: A) 0, 1, and 2 months; B) 0, 1, and 6 months; and C) 0, 1, and 12 months. Among 46 participant available for follow-up, 40 (87%) maintained protective levels of anti-hepatitis A antibody. These results indicate that a supplemental booster dose is not yet necessary at or before the 22-year time point.