2015-2016 Vaccine Effectiveness of Live Attenuated and Inactivated Influenza Vaccines in Children in the United States

Clin Infect Dis. 2018 Feb 10;66(5):665-672. doi: 10.1093/cid/cix869.


Background: In the 2015-2016 season, quadrivalent live attenuated influenza vaccine (LAIV) and both trivalent and quadrivalent inactivated influenza vaccine (IIV) were available in the United States.

Methods: This study, conducted according to a test-negative case-control design, enrolled children aged 2-17 years presenting to outpatient settings with fever and respiratory symptoms for <5 days at 8 sites across the United States between 30 November 2015 and 15 April 2016. A nasal swab was obtained for reverse-transcriptase polymerase chain reaction (RT-PCR) testing for influenza, and influenza vaccination was verified in the medical record or vaccine registry. Influenza vaccine effectiveness (VE) was estimated using a logistic regression model.

Results: Of 1012 children retained for analysis, most children (59%) were unvaccinated, 10% received LAIV, and 31% received IIV. Influenza A (predominantly antigenically similar to the A/California/7/2009 strain) was detected in 14% and influenza B (predominantly a B/Victoria lineage) in 10%. For all influenza, VE was 46% (95% confidence interval [CI], 7%-69%) for LAIV and 65% (48%-76%) for IIV. VE against influenza A(H1N1)pdm09 was 50% (95% CI, -2% to 75%) for LAIV and 71% (51%-82%) for IIV. The odds ratio for vaccine failure with RT-PCR-confirmed A(H1N1)pdm09 was 1.71 (95% CI, 0.78-3.73) in LAIV versus IIV recipients.

Conclusions: LAIV and IIV demonstrated effectiveness against any influenza among children aged 2-17 years in 2015-2016. When compared to all unvaccinated children, VE against influenza A(H1N1)pdm09 was significant for IIV but not LAIV.

Clinical trials registration: NCT01997450.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Influenza A Virus, H1N1 Subtype
  • Influenza A Virus, H3N2 Subtype
  • Influenza B virus
  • Influenza Vaccines / immunology
  • Influenza Vaccines / therapeutic use*
  • Influenza, Human / epidemiology
  • Influenza, Human / prevention & control*
  • Logistic Models
  • Male
  • Nose / virology
  • Seasons
  • United States / epidemiology
  • Vaccination / statistics & numerical data
  • Vaccine Potency*
  • Vaccines, Attenuated / immunology
  • Vaccines, Attenuated / therapeutic use
  • Vaccines, Inactivated / immunology
  • Vaccines, Inactivated / therapeutic use


  • Influenza Vaccines
  • Vaccines, Attenuated
  • Vaccines, Inactivated

Associated data

  • ClinicalTrials.gov/NCT01997450