title: Immunogenicity of a 2009 pandemic influenza virus A H1N1 vaccine, administered simultaneously with the seasonal influenza vaccine, in children receiving chemotherapy.
abstract: BACKGROUND
  No examination of simultaneous vaccination against pandemic H1N1 and the seasonal influenza virus strains, in children with cancer receiving chemotherapy, are yet published. We investigated the immunogenicity of a whole-virion, inactivated, adjuvanted pandemic H1N1, and seasonal influenza vaccines administered simultaneously to children with cancer undergoing chemotherapy.
  
  
  METHODS
  We prospectively enrolled 27 pediatric patients receiving therapy for various types of cancer. All received influenza vaccination once in a seasonal risk period. We checked hemaglutination-inhibition (HAI) antibody titers in the sera of patients before, and 21-28 days after vaccination. Seroprotective titer was defined as an antibody titer ≥ 40, and seroresponse as ≥ 4-fold increase in antibody titers after vaccination.
  
  
  RESULTS
  The pre- and post-vaccination seroprotective rates were H1N1: 33-48%, H3N2: 56-78%, B: 0-15% for seasonal influenza, and for pandemic H1N1: 15-37%. The seroresponse rates for seasonal influenza H1N1, H3N2, and B were 22%, 37%, and 22%, respectively, and 30% for the pandemic H1N1 vaccine.
  
  
  CONCLUSIONS
  Whole-virion, inactivated, adjuvanted vaccine for the pandemic H1N1 Influenza A virus and the seasonal influenza vaccines were found safe and partially immunogenic in children with cancer receiving chemotherapy. The only determinants of responsiveness were lymphocyte count and serum immunoglobulin-G. Only influenza B vaccine elicited significant differences in differences in pre- and post-vaccination seroprotective rates. The response to vaccination for pandemic H1N1 is as effective as other vaccines, however administration of a single vaccine during chemotherapy is more comfortable for pediatric cancer patients.
authors.affiliation: Division of Pediatric Hematology and Oncology, Department of Pediatrics, Faculty of Medicine, University of Pécs, Pécs, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Ottóffy
authors.forename: Petra
authors.initials: P
authors.lastname: Horváth
authors.forename: Lajos
authors.initials: L
authors.lastname: Muth
authors.forename: Alexander
authors.initials: A
authors.lastname: Sólyom
authors.forename: Miklós
authors.initials: M
authors.lastname: Garami
authors.forename: Gábor
authors.initials: G
authors.lastname: Kovács
authors.forename: Tibor
authors.initials: T
authors.lastname: Nyári
authors.forename: Dénes
authors.initials: D
authors.lastname: Molnár
authors.forename: Gábor
authors.initials: G
authors.lastname: Pauler
authors.forename: István
authors.initials: I
authors.lastname: Jankovics
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000096:biosynthesis*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D005260:Female; D019337:Hematologic Neoplasms / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000139:chemically induced* / Q000276:immunology; D008297:Male; D009369:Neoplasms / Q000188:drug therapy / Q000276:immunology*; D016865:Reassortant Viruses / Q000276:immunology; D012621:Seasons; D014611:Vaccination / Q000379:methods; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014771:Virion / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
keywords: chemotherapy; influenza; pandemic H1N1; pediatric oncology; vaccine