title: Immunogenicity and Safety of 2 Dose Levels of a Thimerosal-Free Trivalent Seasonal Influenza Vaccine in Children Aged 6-35 Months: A Randomized, Controlled Trial.
abstract: BACKGROUND
  Improved influenza vaccine strategies for infants and preschool children are a high priority.
  
  
  METHODS
  The immunological response and safety of a thimerosal-free trivalent inactivated influenza vaccine at 2 different doses (0.50 mL vs 0.25 mL) was evaluated in children aged 6-35 months. The study was randomized, observer blind, multicenter, and stratified by age (6-23 months and 24-35 months), and it accounted for prior influenza immunization status.
  
  
  RESULTS
  Three hundred seventy-four children were in the total vaccinated cohort (study vaccine 0.25-mL dose, n = 164; 0.50-mL dose, n = 167; comparator 0.25 mL, n = 43). Regulatory criteria for immunogenicity of influenza vaccines in adults were met for all virus strains and doses for both age strata. A modest but not statistically significant improvement in immune responses was observed with the higher dose and reactogenicity, and safety of the 2 doses was not significantly different.
  
  
  CONCLUSIONS
  The 0.5-mL dose of the study vaccine, when administered to children aged 6-35 months, resulted in a modest but not statistically significant improvement in immunogenicity with clinically similar safety and reactogenicity compared with the 0.25-mL dose. Further studies comparing full- and half-dose influenza vaccine in young children are needed.
  
  
  BACKGROUND
  NCT00778895.
authors.affiliation: Canadian Center for Vaccinology Dalhousie University IWK Health Centre Halifax, Nova Scotia jmlangle@dal.ca.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Langley
authors.affiliation: University of Calgary.
authors.forename: Otto G
authors.initials: OG
authors.lastname: Vanderkooi
authors.affiliation: University of Toronto, Ontario.
authors.forename: Hartley A
authors.initials: HA
authors.lastname: Garfield
authors.affiliation: Allergy and Immunology, Centre Hospitalier Universitaire de Québec, Canada.
authors.forename: Jacques
authors.initials: J
authors.lastname: Hebert
authors.affiliation: GlaxoSmithKline Biologicals, King of Prussia, Pennsylvania.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Chandrasekaran
authors.affiliation: GlaxoSmithKline Biologicals, King of Prussia, Pennsylvania.
authors.forename: Varsha K
authors.initials: VK
authors.lastname: Jain
authors.affiliation: GlaxoSmithKline Biologicals, Columbia, Maryland.
authors.forename: Louis
authors.initials: L
authors.lastname: Fries