Long-term persistence of anti-HAV antibody conferred by a single dose of live-attenuated hepatitis A vaccine: Results from 17-year follow-up

In 1996, 3,515 susceptible children aged one to 12 years were recruited in a randomized, open trial to assess the efficacy of a live-attenuated HA vaccine. A comprehensive and systematic assessment of long-term persistence of anti-HAV antibodies, as well as protection against infection conferred by vaccine was performed based on this cohort. During the 17-year follow-up, the sero-positive rate and the geometric mean concentrations declined from 94.9% and 131.3 mIU/mL (91.5-188.4mIU/mL) at the peak to 55.6% and 41.1 mIU/mL (95% CI: 27.8-61.0 mIU/mL) respectively, with a similar natural infection rate in both groups. These results suggest that a booster dose is currently not necessary.