title: Safety and immunogenicity of a quadrivalent inactivated influenza vaccine compared to licensed trivalent inactivated influenza vaccines in adults.
abstract: OBJECTIVE
  To evaluate the safety and immunogenicity of a prototype quadrivalent inactivated influenza vaccine (QIV) containing two influenza B strains, one of each lineage, compared with licensed trivalent inactivated influenza vaccines (TIVs) containing either a Victoria B-lineage strain (2009-2010 TIV) or a Yamagata B-lineage strain (2008-2009 TIV).
  
  
  METHODS
  Healthy adults ≥18 years of age were eligible to participate in this phase II, open-label, randomized, controlled, multicenter study conducted in the US. Participants received a single dose of 2009-2010 TIV, 2008-2009 TIV, or QIV. Sera were collected before and 21 days after vaccine administration to test for hemagglutination inhibition (HAI) antibodies to each of the four influenza strains. Immunogenicity endpoints included geometric mean HAI antibody titers (GMTs) and rates of seroprotection (titer ≥1:40) and seroconversion (4-fold rise pre- to post-vaccination). Safety endpoints included frequency of solicited injection-site and systemic reactions occurring within 3 days of vaccination, and unsolicited non-serious adverse events (AEs) and serious AEs (SAEs) within 21 days of vaccination.
  
  
  RESULTS
  One hundred and ninety participants were enrolled to each vaccine group. QIV induced GMTs to each A and B strain that were noninferior to those induced by the 2009-2010 and 2008-2009 TIVs (i.e., lower limit of the two-sided 95% confidence interval of the ratio of GMT(QIV)/GMT(TIV)>0.66 for each strain). Rates of seroprotection and seroconversion were similar in all groups. Incidence and severity of solicited injection-site and systemic reactions, AEs, and SAEs were similar among groups.
  
  
  CONCLUSIONS
  QIV, containing two B strains (one from each B lineage), was as safe and immunogenic as licensed TIV. QIV has the potential to be a useful alternative to TIV and offer protection against both B lineages.
authors.affiliation: Sanofi Pasteur, Swiftwater, PA 18370, USA. David.Greenberg@sanofipasteur.com
authors.forename: David P
authors.initials: DP
authors.lastname: Greenberg
authors.forename: Corwin A
authors.initials: CA
authors.lastname: Robertson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Noss
authors.forename: Mark M
authors.initials: MM
authors.lastname: Blatter
authors.forename: Rex
authors.initials: R
authors.lastname: Biedenbender
authors.forename: Michael D
authors.initials: MD
authors.lastname: Decker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D044967:Serum / Q000276:immunology; D014481:United States; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated