title: Persistence of seropositivity among persons vaccinated for hepatitis A during infancy by maternal antibody status: 15-year follow-up.
abstract: The effect of passively transferred maternal antibody to hepatitis A virus (anti-HAV) on the duration of seropositivity after hepatitis A vaccination during infancy and early childhood is unclear. We obtained levels of anti-HAV at intervals through age 15-16 years among three groups of Alaskan Native children who initiated a two-dose inactivated hepatitis A vaccination series at ages 6 months (group 1), 12 months (group 2), and 15 months (group 3), each group randomized according to maternal anti-HAV status. Seropositivity (anti-HAV ≥20 mIU/mL) 30 years after the second vaccine dose among the three groups was predicted using a random effects model. One hundred eighty-three children participated in the study; follow-up did not differ significantly by vaccine group or maternal anti-HAV status. Although the frequency of seropositivity among all participants through age 10 years was high (100% among groups 2 and 3 and >90% among group 1), there was a decrease thereafter through age 15-16 years among group 1 children, who initiated vaccination at age 6 months (50%-75%), and among maternal anti-HAV-positive children in groups 2 and 3 (67%-87%), who initiated vaccination at ages 12 months and 15 months, respectively. Nonetheless, the model indicated that anti-HAV seropositivity should persist for ≥30 years after vaccination in 64% of all participants; among those seropositive at age 15-16 years, 84% were predicted to remain so for ≥30 years.
  
  
  CONCLUSIONS
  Most children vaccinated during early childhood available for sampling maintained seropositivity through age 15-16 years; however, seropositivity was less frequent among those starting vaccination at age 6 months and among maternal antibody-positive participants who started vaccination at age 12 months or 15 months; overall, our findings support current vaccine recommendations and continued follow-up of this cohort.
authors.affiliation: Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, GA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Spradling
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, AK.
authors.forename: Lisa R
authors.initials: LR
authors.lastname: Bulkow
authors.affiliation: Liver Disease and Hepatitis Program, Alaska Native Tribal Health Consortium, Anchorage, AK.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Negus
authors.affiliation: Liver Disease and Hepatitis Program, Alaska Native Tribal Health Consortium, Anchorage, AK.
authors.forename: Chriss
authors.initials: C
authors.lastname: Homan
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, AK.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bruce
authors.affiliation: Arctic Investigations Program, Division of Preparedness and Emerging Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, AK.|Liver Disease and Hepatitis Program, Alaska Native Tribal Health Consortium, Anchorage, AK.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: McMahon
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000413:Alaska; D005260:Female; D005500:Follow-Up Studies; D006506:Hepatitis A / Q000276:immunology*; D022362:Hepatitis A Vaccines / Q000276:immunology*; D006801:Humans; D007198:Indians, North American; D007223:Infant; D018811:Maternal Exposure
chemical_list: D022362:Hepatitis A Vaccines