23470239

PMC4648811

CC999999/Intramural CDC HHS/United States
U01PS001097/PS/NCHHSTP CDC HHS/United States
U50/CCU022279/PHS HHS/United States

CDC Public Access
Arctic Investigations Program

Background

Hepatitis A is mostly a self-limiting disease but causes substantial economic burden. Consequently, United States Advisory Committee for Immunization Practices recommends inactivated hepatitis A vaccination for all children beginning at age 1 year and for high risk adults. The hepatitis A vaccine is highly effective but the duration of protection is unknown.

Methods

We examined the proportion of children with protective hepatitis A antibody levels (anti-HAV ≥20 mIU/mL) as well as the geometric mean concentration (GMC) of anti-HAV in a cross sectional convenience sample of individuals aged 12–24 years, who had been vaccinated with a two-dose schedule in childhood, with the initial dose at least 5 years ago. We compared a subset of data from persons vaccinated with two-doses (720 EL.U.) at age 3–6 years with a demographically similar prospective cohort that received a three-dose (360 EL.U.) schedule and have been followed for 17 years.

Results

No significant differences were observed when comparing GMC between the two cohorts at 10 (P = 0.467), 12 (P = 0.496), and 14 (P = 0.175) years post-immunization. For the three-dose cohort, protective antibody levels remain for 17 years and have leveled-off over the past 7 years.

Conclusion

The two- and three-dose schedules provide similar protection >14 years after vaccination, indicating a booster dose is not needed at this time. Plateauing anti-HAV GMC levels suggest protective antibody levels may persist long-term.