title: [Seroconversion in response to a reinforced primary hepatitis B vaccination in children with cancer].
abstract: BACKGROUND
  Immune response against vaccine antigens may be impaired in children with cancer. The aim of this study was to evaluate the seroconversion response against hepatitis B vaccination (HBV) at the time of chemotherapy onset and/or remission in children with cancer.
  
  
  METHODS
  Prospective, two-centre, controlled, non-randomised study conducted on children recently diagnosed with cancer, paired with healthy subjects. Cases received HBV at time 0, 1 and 6 months with DNA recombinant HBV at a dose of 20 and 40 μg if < or > than 10 years of age, respectively, at the time of diagnosis for solids tumours and after the remission in case of haematological tumours. Controls received the same schedule, but at of 10 and 20 μg doses, respectively. HBs antibodies were measured in serum samples obtained at 2, 8 and 12 months post-vaccination. Protective titres were defined as > 10 mIU/ml at 8th month of follow up.
  
  
  RESULTS
  A total of 78 children with cancer and 25 healthy controls were analysed at month 8th of follow up. Seroconversion rates in the cancer group reached 26.9%, with no differences by age, gender or type of tumour (P = .13, .29, and .44, respectively). Control group seroconversion was 100% at the 8th month, with P < .0001 compared with the cancer group. At month 12 of follow up, just 31.9% of children with cancer achieved anti-HBs antibodies > 10 mIU/ml.
  
  
  CONCLUSIONS
  Vaccination against hepatitis B with three doses of DNA recombinant vaccine at an increased concentration, administrated at the time of onset of chemotherapy and/or remission provided an insufficient immune response in a majority of children with cancer. More immunogenic vaccines should be evaluated in this special population, such as a third generation, with more immunogenic adjuvants, enhanced schedules at 0, 1, 2, 6 month, evaluation of antibody titres at month 8 and 12h to evaluate the need for further booster doses.
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Hospital de niños Dr. Exequiel González Cortés, Santiago, Chile. Electronic address: rodolfo.villena@redsalud.gov.cl.
authors: Rodolfo
authors: R
authors: Villena
authors: Hospital de niños Dr. Exequiel González Cortés, Santiago, Chile; Programa Infantil Nacional de Drogas Antineoplásicas (PINDA), Santiago, Chile; Fundación Nuestros Hijos, Santiago, Chile.
authors: Marcela
authors: M
authors: Zubieta
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Laboratorio de Gastroenterología, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors: Carmen
authors: C
authors: Hurtado
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Hospital de niños Dr. Exequiel González Cortés, Santiago, Chile; Programa Infantil Nacional de Drogas Antineoplásicas (PINDA), Santiago, Chile.
authors: Carmen
authors: C
authors: Salgado
authors: Hospital de niños Dr. Exequiel González Cortés, Santiago, Chile.
authors: Gladys
authors: G
authors: Silva
authors: Fundación Nuestros Hijos, Santiago, Chile.
authors: Jazmine
authors: J
authors: Fernández
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Programa Infantil Nacional de Drogas Antineoplásicas (PINDA), Santiago, Chile; Hospital de niños Dr. Luis Calvo Mackenna, Santiago, Chile.
authors: Milena
authors: M
authors: Villarroel
authors: Hospital de niños Dr. Luis Calvo Mackenna, Santiago, Chile.
authors: Marisol
authors: M
authors: Fernández
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Laboratorio de Gastroenterología, Hospital Clínico Universidad de Chile, Santiago, Chile.
authors: Javier
authors: J
authors: Brahm
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors: Miguel
authors: M
authors: O'Ryan
authors: Facultad de Medicina, Universidad de Chile, Santiago, Chile; Programa Infantil Nacional de Drogas Antineoplásicas (PINDA), Santiago, Chile; Hospital de niños Dr. Luis Calvo Mackenna, Santiago, Chile.
authors: María Elena
authors: ME
authors: Santolaya
mesh_terms: D000293:Adolescent; D000970:Antineoplastic Agents / Q000008:administration & dosage; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D009369:Neoplasms / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D011446:Prospective Studies; D000069078:Seroconversion; D013997:Time Factors; D014611:Vaccination; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000970:Antineoplastic Agents; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D019444:Vaccines, DNA
keywords: Children with cancer; DNA recombinant vaccine; Hepatitis B; Niños con cáncer; Vacuna ADN recombinante