title: Viral interference and the live-attenuated intranasal influenza vaccine: Results from a pediatric cohort with cystic fibrosis.
abstract: The objective of this study was to explore the effects of viral co-detection in individuals recently vaccinated with the live-attenuated intranasal influenza virus vaccine (LAIV) on the detection of influenza RNA.
  
  
  
  Before the 2013-2014 influenza season, nasal swabs were obtained from 59 pediatric participants with cystic fibrosis (CF) and 17 of their healthy siblings immediately before vaccination and 4 times during the week of follow-up. Real-time RT-PCR assays were used to detect influenza RNA. Co-detection of a non-influenza respiratory virus (NIRV) at the time of vaccination was determined by a multiplex RT-PCR assay. Differences in the proportions and rates of influenza detection and their 95% credible intervals (CrI) were estimated.
  
  
  
  Influenza RNA was detected in 16% fewer participants (95% CrI: -7, 39%) throughout follow-up in the NIRV-positive group compared with the NIRV-negative group (59% vs. 75%). This was also observed in participants with CF alone (66% vs. 74%; RD = 8% 95% CrI: -16, 33%) as well as in healthy participants only (75% vs. 30%; RD = 45%, 95% CrI: -2, 81%). Influenza was detected in NIRV-negative subjects for 0.49 d more compared with NIRV-positive subjects (95% CrI: -0.37, 1.26).
  
  
  
  The observed proportion of subjects in whom influenza RNA was detected and the duration of detection differed slightly between NIRV- positive and -negative subjects. However, wide credible intervals for the difference preclude definitive conclusions. If true, this observed association may be related to a recent viral respiratory infection, a phenomenon known as viral interference.
authors.affiliation: a Department of Epidemiology , Biostatistics & Occupational Health, McGill University , Montreal , QC , Canada.
authors.forename: Constantina
authors.initials: C
authors.lastname: Boikos
authors.affiliation: b Department of Pediatrics , Division of Infectious Diseases, The Montreal Children's Hospital, McGill University , Montreal , QC , Canada.
authors.forename: Jesse
authors.initials: J
authors.lastname: Papenburg
authors.affiliation: c Laboratoire de santé publique du Québec, Institut national de santé publique du Québec , QC , Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: Martineau
authors.affiliation: a Department of Epidemiology , Biostatistics & Occupational Health, McGill University , Montreal , QC , Canada.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Joseph
authors.affiliation: d Vaccine Evaluation Center, Child & Family Research Institute, University of British Columbia , BC , Canada.
authors.forename: David
authors.initials: D
authors.lastname: Scheifele
authors.affiliation: e Director, Cystic Fibrosis Clinic, University of British Columbia , BC , Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Chilvers
authors.affiliation: f Department of Pediatrics , Division of Respiratory Medicine, The Montreal Children's Hospital, McGill University , Montreal , QC , Canada.
authors.forename: Larry C
authors.initials: LC
authors.lastname: Lands
authors.affiliation: g Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec , QC , Canada.
authors.forename: Gaston
authors.initials: G
authors.lastname: De Serres
authors.affiliation: a Department of Epidemiology , Biostatistics & Occupational Health, McGill University , Montreal , QC , Canada.|b Department of Pediatrics , Division of Infectious Diseases, The Montreal Children's Hospital, McGill University , Montreal , QC , Canada.|g Direction des risques biologiques et de la santé au travail, Institut national de santé publique du Québec , QC , Canada.|h McGill University Health Centre, Vaccine Study Centre, Research Institute of the MUHC , Montreal , QC , Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Quach
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D060885:Multiplex Polymerase Chain Reaction; D009975:Orthomyxoviridae / Q000502:physiology*; D011446:Prospective Studies; D012328:RNA Viruses / Q000302:isolation & purification*; D012367:RNA, Viral / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D014762:Viral Interference; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D012367:RNA, Viral; D014613:Vaccines, Attenuated
keywords: childhood vaccination; cystic fibrosis; influenza vaccination; live-attenuated influenza virus vaccine; viral interference