title: Efficacy of a Russian-backbone live attenuated influenza vaccine among children in Senegal: a randomised, double-blind, placebo-controlled trial.
abstract: Live attenuated influenza vaccines have been shown to significantly reduce influenza in diverse populations of children, but no efficacy studies have been done in resource-poor tropical settings. In Senegal, we assessed the efficacy and safety of a live attenuated influenza vaccine based on Russian-derived master donor viruses and licensed as a single dose.
  
  
  
  In this double-blind, placebo-controlled, parallel group, single-centre trial done near Niakhar, Senegal, generally healthy children aged 2-5 years were randomly allocated (2:1) to receive a single intranasal dose of masked trivalent live attenuated influenza vaccine or placebo. The allocation sequence was computer-generated by PATH with block sizes of three. The manufacturer provided vaccine and placebo in coded vials to preserve blinding. Participants were monitored through the predictable influenza season in Senegal for adverse events and signs and symptoms of influenza using weekly home visits and surveillance in clinics. The primary outcome was symptomatic laboratory-confirmed influenza caused by any strain and occurring from 15 days post-vaccination to the end of the study. The primary analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT01854632.
  
  
  
  Between May 23, and July 1, 2013, 1761 children were randomly assigned, 1174 to receive live attenuated influenza vaccine and 587 to receive placebo. The per-protocol set included 1173 vaccinees and 584 placebo recipients followed up to Dec 20, 2013. Symptomatic influenza was laboratory-confirmed in 210 (18%) of 1173 recipients of live attenuated influenza vaccine and 105 (18%) of placebo recipients, giving a vaccine efficacy of 0·0% (95% CI -26·4 to 20·9). Adverse events were balanced between the study groups. Two girls who had received live attenuated influenza vaccine died, one due to anasarca 12 days postvaccination and one due to malnutrition 70 days postvaccination.
  
  
  
  Live attenuated influenza vaccine was well tolerated in young children in Senegal, but did not provide protection against influenza. Further study in such populations, which might experience extended periods of influenza circulation, is warranted.
  
  
  
  US Centers for Disease Control and Prevention and Bill & Melinda Gates Foundation.
authors.affiliation: PATH, Seattle, WA, USA. Electronic address: cvictor@path.org.
authors.forename: John C
authors.initials: JC
authors.lastname: Victor
authors.affiliation: PATH, Seattle, WA, USA.
authors.forename: Kristen D C
authors.initials: KD
authors.lastname: Lewis
authors.affiliation: Mixed Research Unit 198, Institut de Recherche Pour le Développement, Dakar, Senegal.
authors.forename: Aldiouma
authors.initials: A
authors.lastname: Diallo
authors.affiliation: Senegal National Influenza Center, Institut Pasteur de Dakar, Dakar, Senegal.
authors.forename: Mbayame N
authors.initials: MN
authors.lastname: Niang
authors.affiliation: Mixed Research Unit 198, Institut de Recherche Pour le Développement, Dakar, Senegal.
authors.forename: Bou
authors.initials: B
authors.lastname: Diarra
authors.affiliation: Senegal National Influenza Center, Institut Pasteur de Dakar, Dakar, Senegal.
authors.forename: Ndongo
authors.initials: N
authors.lastname: Dia
authors.affiliation: PATH, Seattle, WA, USA; Departments of Global Health and Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Ortiz
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Marc-Alain
authors.initials: MA
authors.lastname: Widdowson
authors.affiliation: PATH, Seattle, WA, USA.
authors.forename: Jodi
authors.initials: J
authors.lastname: Feser
authors.affiliation: Cota Enterprises Inc, McLouth, KS, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hoagland
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Emery
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Lafond
authors.affiliation: Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Neuzil
mesh_terms: D000281:Administration, Intranasal / Q000379:methods; D002675:Child, Preschool; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D012675:Senegal; D014611:Vaccination / Q000379:methods; D014613:Vaccines, Attenuated / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated