title: Effectiveness of live attenuated influenza vaccine and inactivated influenza vaccine in children 2-17 years of age in 2013-2014 in the United States.
abstract: BACKGROUND
  A postmarketing observational study was initiated to evaluate quadrivalent live attenuated influenza vaccine (LAIV) effectiveness in children aged 2-17 years in the United States.
  
  
  METHODS
  Children and adolescents aged 2-17 years seeking outpatient care for febrile acute respiratory illness <5 days duration were enrolled at 4 geographically diverse sites during the 2013-2014 influenza season. Nasal swabs were tested for influenza using reverse transcription polymerase chain reaction. Vaccination status was documented from medical records or immunization registries. Children who received ≥1 dose of influenza vaccine ≥14 days before study visit were considered vaccinated. Vaccine effectiveness (VE) was estimated as 100×(1-adjusted odds ratio), where the odds of interest are the odds of vaccine exposure among influenza cases and test-negative controls.
  
  
  RESULTS
  In total, 1033 children and adolescents were included in the analysis. Influenza was detected in 14% (145/1033) of all children, with 74% (108/145) of the influenza cases due to A/H1N1pdm09 strains, 21% (31) to influenza B, and 4% (6) to influenza H3N2. LAIV did not show significant effectiveness against A/H1N1pdm09 (VE 13% [95% CI: -55 to 51]) but was effective against B/Yamagata strains (82% [95% CI: 12-96]). Inactivated influenza vaccine was effective against A/H1N1pdm09 (74% [95% CI: 50-86]) and B/Yamagata (70% [95% CI: 18-89]).
  
  
  CONCLUSIONS
  LAIV provided significant protection against B/Yamagata influenza but not against A/H1N1pdm09 in children aged 2-17 years in 2013-2014, resulting in a proposed change of the 2015-2016 formulation with a new and more heat-stable A/H1N1pdm09 LAIV strain.
authors.affiliation: AstraZeneca, One MedImmune Way, Gaithersburg, MD 20878, United States. Electronic address: caspardh@medimmune.com.
authors.forename: Herve
authors.initials: H
authors.lastname: Caspard
authors.affiliation: Baylor Scott & White Health, Texas A&M Health Science Center College of Medicine, 2401 South 31st Street, Temple, TX 76508, United States. Electronic address: mgaglani@sw.org.
authors.forename: Manjusha
authors.initials: M
authors.lastname: Gaglani
authors.affiliation: Baylor Scott & White Health, Texas A&M Health Science Center College of Medicine, 2401 South 31st Street, Temple, TX 76508, United States. Electronic address: lclipper@sw.org.
authors.forename: Lydia
authors.initials: L
authors.lastname: Clipper
authors.affiliation: Marshfield Clinic Research Foundation, 1000 N. Oak Avenue, Marshfield, WI 54449, United States. Electronic address: belongia.edward@marshfieldclinic.org.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Belongia
authors.affiliation: Marshfield Clinic Research Foundation, 1000 N. Oak Avenue, Marshfield, WI 54449, United States. Electronic address: mclean.huong@marshfieldclinic.org.
authors.forename: Huong Q
authors.initials: HQ
authors.lastname: McLean
authors.affiliation: Vanderbilt University Medical Center, 1161 21st Avenue S, Nashville, TN 37232, United States. Electronic address: marie.griffin@vanderbilt.edu.
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.affiliation: Vanderbilt University Medical Center, 1161 21st Avenue S, Nashville, TN 37232, United States. Electronic address: keipp.talbot@vanderbilt.edu.
authors.forename: H Keipp
authors.initials: HK
authors.lastname: Talbot
authors.affiliation: Wake Forest School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC 27157, United States. Electronic address: kpoehlin@wfubmc.edu.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Poehling
authors.affiliation: Wake Forest School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC 27157, United States. Electronic address: tpeters@wakehealth.edu.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Peters
authors.affiliation: AstraZeneca, One MedImmune Way, Gaithersburg, MD 20878, United States. Electronic address: veneyn@medimmune.com.
authors.forename: Naomi
authors.initials: N
authors.lastname: Veney
authors.affiliation: AstraZeneca, One MedImmune Way, Gaithersburg, MD 20878, United States. Electronic address: ambrosec@medimmune.com.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ambrose
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated
keywords: LAIV; Pediatrics; Quadrivalent live attenuated influenza vaccine