title: Clinical efficacy of cell culture–derived and egg‐derived inactivated subunit influenza vaccines in healthy adults.
abstract: BACKGROUND
  More efficient methods are needed to manufacture influenza vaccines. This trial compared the efficacy of cell culture-derived influenza vaccine (CCIV) and egg-derived trivalent inactivated vaccine (TIV) with placebo against laboratory-confirmed influenza illness in healthy adults in the United States, Finland, and Poland during the 2007-2008 influenza season.
  
  
  METHODS
  A total of 11,404 study participants aged 18-49 years were randomized equally to receive CCIV (Optaflu; n = 3828), TIV (Agrippal; n = 3676), or placebo (n = 3900). Each participant was observed during a 6-month study surveillance period. Nasal and throat swabs for virus isolation and characterization were collected from all patients with influenza-like illness. Vaccine immunogenicity was evaluated in a subset of 1045 participants.
  
  
  RESULTS
  Efficacy of CCIV and TIV against vaccine-like (83.8% [1-sided 97.5% confidence interval [CI] lower limit, 61.0%] and 78.4% [1-sided 97.5% CI lower limit, 52.1%], respectively) and all circulating influenza virus strains (69.5% [1-sided 97.5% CI lower limit, 55.0%] and 63.0% [1-sided 97.5% lower limit, 46.7%], respectively) exceeded the Center for Biologics Evaluation and Research efficacy criteria. Immunogenicity of both vaccines exceeded the Center for Biologics Evaluation and Research licensing criteria. Both vaccines were well tolerated, with similar safety profiles. Most solicited reactions were mild to moderate in severity and transient. No vaccination-related serious adverse events were reported; no withdrawals resulted from vaccine-related adverse events.
  
  
  CONCLUSIONS
  Both CCIV and TIV were effective in preventing influenza caused by vaccine-like and by all circulating influenza virus strains, were well tolerated, and had good safety profiles. Both vaccines can be considered for annual influenza vaccination campaigns.
  
  
  BACKGROUND
  NCT00630331.
authors.affiliation: Saint Louis University Medical School, St. Louis, Missouri, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Frey
authors.forename: Timo
authors.initials: T
authors.lastname: Vesikari
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Szymczakiewicz-Multanowska
authors.forename: Maria
authors.initials: M
authors.lastname: Lattanzi
authors.forename: Allen
authors.initials: A
authors.lastname: Izu
authors.forename: Nicola
authors.initials: N
authors.lastname: Groth
authors.forename: Sandra
authors.initials: S
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000328:Adult; D018929:Cell Culture Techniques; D005260:Female; D005387:Finland; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000821:virology; D009975:Orthomyxoviridae / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D010614:Pharynx / Q000821:virology; D010919:Placebos / Q000008:administration & dosage; D011044:Poland; D013678:Technology, Pharmaceutical; D014481:United States; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D010919:Placebos; D015164:Vaccines, Inactivated; D022223:Vaccines, Subunit