Safety and immunogenicity of an inactivated quadrivalent influenza vaccine in children 6 months through 8 years of age

Pediatr Infect Dis J. 2014 Jun;33(6):630-6. doi: 10.1097/INF.0000000000000254.


Background: Strains of 2 distinct influenza B lineages (Victoria and Yamagata) have cocirculated in the United States for over a decade, but trivalent influenza vaccines (TIVs) contain only 1 B-lineage strain. Each season, some or most influenza B disease is caused by the B lineage not represented in that season's TIV. Quadrivalent influenza vaccines (QIVs) containing a strain from each B lineage should resolve this problem.

Methods: This was a Phase III, randomized, multicenter trial in the United States among children 6 months to <9 years of age to evaluate the safety and immunogenicity of inactivated QIV compared with inactivated control TIVs containing opposite B-lineage strains. Participants were randomized at a ratio of approximately 4:1:1 to receive QIV, TIV containing a Victoria-lineage B strain or TIV containing a Yamagata-lineage B strain. Sera were collected pre- and 28-days post-final vaccination and safety was assessed for 6 months after the last injection.

Results: A total of 4363 participants were enrolled. QIV induced noninferior antibody responses to all A strains and corresponding B strains compared with the control TIVs and superior antibody responses to the noncorresponding B strain in each TIV. Rates of solicited reactions and unsolicited and serious adverse events were similar in all groups.

Conclusions: This study demonstrated that QIV is safe and immunogenic among children 6 months to <9 years of age. These findings, along with data from 2 other studies of this QIV in adults, suggest that QIV should offer protection against both B lineages with a safety profile similar to TIV across all ages.

Publication types

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

MeSH terms

  • Antibodies, Viral / blood
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / adverse effects*
  • Influenza Vaccines / immunology*
  • Influenza, Human / epidemiology
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control
  • Male
  • Orthomyxoviridae / immunology
  • United States / epidemiology
  • Vaccines, Inactivated / administration & dosage
  • Vaccines, Inactivated / adverse effects*
  • Vaccines, Inactivated / immunology*


  • Antibodies, Viral
  • Influenza Vaccines
  • Vaccines, Inactivated