title: Evaluation of immune responses to combined hepatitis A and B vaccine in HIV-infected children and children on immunosuppressive medication.
abstract: OBJECTIVE
  A phase IV interventional study with a combined hepatitis A and B vaccine was conducted in HIV-infected children and children receiving immunosuppressive medication for treatment of rheumatic diseases to evaluate immune responses.
  
  
  METHODS
  Both groups (1-16 years of age) received combined (inactivated) HAV and (rDNA) HBV vaccine Ambirix(®) at months 0 and 6. Serum samples were taken at four time points and tested for anti-HAV and anti-HBs antibodies. Anti-HAV concentrations ≥20 mIU/mL or anti-HBs concentrations ≥10 mIU/mL were considered protective. Seropositivity percentages were calculated and geometric mean concentrations (GMCs) were compared by nonparametric Mann-Whitney U-test or Kruskal-Wallis one-way-analysis-of-variance.
  
  
  RESULTS
  Of 80 HIV-infected children who completed the study, 67 were HAV-susceptible and 68 HBV-susceptible at enrolment. Of 80 children with rheumatic diseases who completed the study, 65 were HAV-susceptible and 74 HBV-susceptible at enrolment. Immune responses to HAV after first dose of vaccine in both study groups were low: 71% and 55% respectively, whereas immune responses after the second dose were 99% and 100% respectively. Immune response to HBV after first dose of vaccine in both groups was also low: 27% and 17% respectively. Immune responses after the second dose were 97% and 93%, respectively. A larger proportion of children on combination antiretroviral therapy (cART) and of children with viral load <50 copies/mL responded to HBV, and also showed a significantly higher GMC.
  
  
  CONCLUSIONS
  Although immune response after full series of combined HAV and HBV vaccine in both groups was excellent and comparable to healthy children, a substantial proportion of both groups was not protected for HAV after first dose of vaccine. This protection gap is especially important for HAV in travel health and postexposure prophylactic treatment: both groups of children should be serologically tested for anti-HAV prior to travel to ensure protection if there is no time to await second dose of vaccine.
authors.affiliation: Department of Infectious Diseases, Public Health Service (GGD), Amsterdam, The Netherlands. belderoksanne@gmail.com
authors.forename: Sanne-Meike
authors.initials: SM
authors.lastname: Belderok
authors.forename: Gerard J B
authors.initials: GJ
authors.lastname: Sonder
authors.forename: Marion
authors.initials: M
authors.lastname: van Rossum
authors.forename: Annette
authors.initials: A
authors.lastname: van Dijk-Hummelman
authors.forename: Nico
authors.initials: N
authors.lastname: Hartwig
authors.forename: Henriette
authors.initials: H
authors.lastname: Scherpbier
authors.forename: Sibyl
authors.initials: S
authors.lastname: Geelen
authors.forename: Arjen G C L
authors.initials: AG
authors.lastname: Speksnijder
authors.forename: Gijs
authors.initials: G
authors.lastname: Baaten
authors.forename: Anneke
authors.initials: A
authors.lastname: van den Hoek
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology*; D035922:Hepatitis A Antibodies / Q000097:blood; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007223:Infant; D008297:Male; D056990:Post-Exposure Prophylaxis; D012216:Rheumatic Diseases / Q000188:drug therapy / Q000276:immunology; D016896:Treatment Outcome
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D007166:Immunosuppressive Agents
keywords: Combined hepatitis A and B vaccine; HIV-infected children; Hepatitis A; Hepatitis B; Immune response; Rheumatic diseases