title: Persistence of antibody to Hepatitis A virus 20 years after receipt of Hepatitis A vaccine in Alaska.
abstract: Hepatitis A vaccine is recommended for children ≥1 year old to prevent hepatitis A virus (HAV) infection. However, the duration of vaccine-induced immunity is unknown. We evaluated a cohort of Alaska Native persons 20 years after HAV vaccination. Children aged 3-6 years had been previously randomized to receive three doses of HAV vaccine (360 ELISA units/dose) at: (i) 0,1,2 months; (ii) 0,1,6 months; and (iii) 0,1,12 months. We measured anti-HAV antibody concentrations every 2-3 years; described geometric mean concentrations (GMC) and the proportion with protective antibody (≥20 mIU mL-1) over time; and modelled the change in GMC using fractional polynomial regression. Of the 144 participants, after 20 years 52 (36.1%) were available for the follow-up (17, 18, 17 children in Groups A, B and C, respectively). Overall, 46 (88.5%) of 52 available participants had anti-HAV antibody concentrations ≥20 mIU mL-1, and overall GMC was 107 mIU mL-1. Although GMC levels were lower in Group A (60; CI 34-104) than in Group B (110; CI 68-177) or Group C (184; CI 98-345) (B vs C: P=.168; A vs B/C: P=.011), there was no difference between groups after adjusting for peak antibody levels post-vaccination (P=.579). Models predicted geometric mean concentrations of 124 mIU mL-1after 25 years, and 106 mIU mL-1after 30 years. HAV vaccine provides protective antibody levels 20 years after childhood vaccination. Lower antibody levels in Group A may be explained by a lower initial peak response. Our results suggest a booster vaccine dose is unnecessary for at least 25-30 years.
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: I D
authors.identifier: 0000-0003-4747-381X
authors.initials: ID
authors.lastname: Plumb
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Bulkow
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Bruce
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: T W
authors.initials: TW
authors.lastname: Hennessy
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: J
authors.initials: J
authors.lastname: Morris
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infections, Centers for Disease Control and Prevention, Anchorage, AK, USA.
authors.forename: K
authors.initials: K
authors.lastname: Rudolph
authors.affiliation: Epidemiology and Statistics Branch, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: P
authors.initials: P
authors.lastname: Spradling
authors.affiliation: Alaska Native Tribal Health Consortium, Anchorage, AK, USA.
authors.forename: M
authors.initials: M
authors.lastname: Snowball
authors.affiliation: Alaska Native Tribal Health Consortium, Anchorage, AK, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: McMahon
mesh_terms: D000293:Adolescent; D000328:Adult; D000413:Alaska; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology*; D017957:Hepatitis A Virus, Human / Q000276:immunology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D013997:Time Factors; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D022362:Hepatitis A Vaccines
keywords: Hepatitis A; Hepatitis A vaccine; duration of protection; immunogenicity; infectious hepatitis