title: A randomized, controlled trial in children to assess the immunogenicity and safety of a thimerosal-free trivalent seasonal influenza vaccine.
abstract: BACKGROUND
  Children are at high risk of acquiring and transmitting influenza infection and are a high priority group for influenza vaccination.
  
  
  METHODS
  This was a randomized, observer-blind, multicenter study (NCT00980005) based in the United States. Children were randomized (1:1) to receive either the study vaccine, a thimerosal-free trivalent inactivated influenza vaccine or an active comparator (control vaccine) and were allotted to 1 of 3 age categories: 3-4, 5-8 and 9-17 years. The primary objective was to show noninferiority of the study vaccine versus a US- licensed control influenza vaccine.
  
  
  RESULTS
  A total of 2116 children were vaccinated (study vaccine N = 1055, control vaccine N = 1061). The predefined noninferiority criteria and the Center for Biologics Evaluation and Research criteria for clinical benefit were met for all 3 seasonal virus strains in all children and each age strata. The ratios of the adjusted geometric mean titers (control vaccine over study vaccine) ranged from 0.93 to 1.03 for the 3 virus strains whereas the differences in seroconversion rate (control vaccine minus study vaccine) were between -2.42% and -1.60%. Postvaccination geometric mean titers (range: 213.7-414.7 versus 200.2-451.9) and seroconversion rates (range: 59.8-81.1% versus 58.2-78.6%) were comparable for the 2 vaccines. The safety and reactogenicity profiles were similar for both treatment groups in all age strata.
  
  
  CONCLUSIONS
  Immunologic noninferiority of the study vaccine was demonstrated compared with the control vaccine. Furthermore, the study vaccine had a similar safety profile as the control vaccine in children.
authors.affiliation: Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY 13210, USA. domachoj@upstate.edu
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Domachowske
authors.forename: Mark
authors.initials: M
authors.lastname: Blatter
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Chandrasekaran
authors.forename: Aixue
authors.initials: A
authors.lastname: Liu
authors.forename: Varsha K
authors.initials: VK
authors.lastname: Jain
authors.forename: Louis
authors.initials: L
authors.lastname: Fries
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D014481:United States; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated