Safety and immunogenicity of an inactivated thimerosal-free influenza vaccine in infants and children

Influenza Other Respir Viruses. 2009 Nov;3(6):315-25. doi: 10.1111/j.1750-2659.2009.00108.x.


Objective: Few prospective studies of inactivated split virion influenza vaccine have been conducted in infants and children. Our objective was to evaluate the safety, reactogenicity and immunogenicity of a thimerosal-free inactivated influenza vaccine (Fluvax; CSL Limited, Parkville, Australia) in children aged 6 months to <9 years.

Methods: A prospective, open-label, phase III clinical trial was conducted in 298 healthy children previously unvaccinated with influenza, commencing in the Southern Hemisphere 2005 autumn. Participants were divided into two groups (Group A: > or =6 months to <3 years; Group B: > or =3 years to <9 years), and received two doses of the 2005 vaccine, and one dose of the 2006 vaccine one year later (Group A: 0.25 ml per dose; Group B: 0.5 ml per dose). Vaccine safety and reactogenicity was evaluated for 30 days after each dose. Immunogenicity was assessed using hemagglutination inhibition and single radial hemolysis assays.

Results: There were no withdrawals due to adverse events (AEs). The majority of solicited local and systemic AEs were of mild severity. A maximum intensity of severe was reported for injection site pain and fever by only 3.0% and 3.4% of participants, respectively. The vaccine was immunogenic for all antigens, with > or =95% of both younger and older children achieving seroprotection after dose 2.

Conclusions: This thimerosal-free inactivated influenza vaccine had a favorable safety profile and was immunogenic in children aged > or =6 months and <9 years. Primary and booster vaccination produced consistently immunogenic responses including in children under 3 years of age receiving 0.25 ml doses of vaccine.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / blood
  • Australia
  • Child
  • Child, Preschool
  • Drug-Related Side Effects and Adverse Reactions
  • Excipients / pharmacology
  • Female
  • Fever / chemically induced
  • Hemagglutination Inhibition Tests
  • Humans
  • Immunization, Secondary
  • Infant
  • Influenza Vaccines / adverse effects*
  • Influenza Vaccines / immunology*
  • Influenza, Human / prevention & control*
  • Male
  • Pain / chemically induced
  • Thimerosal / pharmacology
  • Vaccines, Inactivated / adverse effects
  • Vaccines, Inactivated / immunology


  • Antibodies, Viral
  • Excipients
  • Influenza Vaccines
  • Vaccines, Inactivated
  • Thimerosal