Superior relative efficacy of live attenuated influenza vaccine compared with inactivated influenza vaccine in young children with recurrent respiratory tract infections

Pediatr Infect Dis J. 2006 Oct;25(10):870-9. doi: 10.1097/01.inf.0000237829.66310.85.

Abstract

Background: Young children have a high incidence of influenza and influenza-related complications. This study compared the efficacy and safety of cold-adapted influenza vaccine, trivalent (CAIV-T) with trivalent inactivated influenza vaccine (TIV) in young children with a history of recurrent respiratory tract infections (RTIs).

Methods: Children 6 to 71 months of age were randomized to receive 2 doses of CAIV-T (n = 1101) or TIV (n = 1086), 35 +/- 7 days apart before the start of the 2002-2003 influenza season and were followed up for culture-confirmed influenza, effectiveness outcomes, reactogenicity, and adverse events.

Results: Overall, 52.7% (95% confidence interval [CI] = 21.6%-72.2%) fewer cases of influenza caused by virus strains antigenically similar to vaccine were observed in CAIV-T than in TIV recipients. Greater relative efficacy for CAIV-T was observed for the antigenically similar A/H1N1 (100.0%; 95% CI = 42.3%-100.0%) and B (68.0%; 95% CI = 37.3%-84.8%) strains but not for the antigenically similar A/H3N2 strains (-97.1%; 95% CI = -540.2% to 31.5%). Relative to TIV, CAIV-T reduced the number of RTI-related healthcare provider visits by 8.9% (90% CI = 1.5%-15.8%) and missed days of school, kindergarten, or day care by 16.2% (90% CI = 10.4%-21.6%). Rhinitis and rhinorrhea, otitis media, and decreased appetite were the only events that were reported more frequently in CAIV-T subjects. There was no difference between groups in the incidence of wheezing after vaccination.

Conclusions: CAIV-T was well tolerated in these children with RTIs and demonstrated superior relative efficacy compared with TIV in preventing influenza illness.

Publication types

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

MeSH terms

  • Administration, Intranasal
  • Child, Preschool
  • Feeding and Eating Disorders / etiology
  • Female
  • Humans
  • Incidence
  • Infant
  • Influenza A Virus, H1N1 Subtype / immunology
  • Influenza A Virus, H3N2 Subtype / immunology
  • Influenza B virus / immunology
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / adverse effects*
  • Influenza Vaccines / immunology*
  • Influenza, Human / epidemiology
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Injections, Intramuscular
  • Male
  • Orthomyxoviridae / classification
  • Orthomyxoviridae / isolation & purification
  • Otitis Media / etiology
  • Recurrence
  • Respiratory Tract Infections* / complications
  • Rhinitis / etiology
  • Vaccines, Attenuated / administration & dosage
  • Vaccines, Attenuated / adverse effects
  • Vaccines, Attenuated / immunology
  • Vaccines, Inactivated / administration & dosage
  • Vaccines, Inactivated / immunology

Substances

  • Influenza Vaccines
  • Vaccines, Attenuated
  • Vaccines, Inactivated