title: Safety of live-attenuated influenza vaccination in cystic fibrosis.
abstract: OBJECTIVE
  Given the improved efficacy of the nasal live-attenuated influenza virus vaccine (LAIV) compared with the injectable vaccine in children, we aimed to determine its safety in individuals with cystic fibrosis (CF).
  
  
  METHODS
  A cohort of 168 study participants, aged 2 to 18 years with CF, vaccinated with LAIV between October 1, 2012, and January 30, 2013, was followed prospectively for 56 days after initial vaccination in 3 pediatric CF clinics across the province of Quebec. Days 0 to 28 post-LAIV were considered the at-risk period for all outcomes of interest, and days 29 to 56 post-LAIV were considered the non-at-risk period. Incident respiratory deteriorations were defined as an unscheduled medical visit, hospitalization, or a new course of oral antibiotics for respiratory complaints. Using a self-controlled design, incidence rate ratios (IRR) were used to compare at-risk and non-at-risk periods.
  
  
  RESULTS
  Comparing at-risk to non-at-risk periods, there was no significant increase in the rate of incident respiratory deteriorations (IRR, 0.72; 95% confidence interval, 0.11-4.27) or all-cause hospitalizations (IRR, 1.16; 95% confidence interval, 0.30-4.81). A greater proportion of participants reported experiencing at least 1 minor respiratory and/or systemic adverse event after immunization during the at-risk period compared with the non-at-risk period (77% vs 54%, respectively). During the first week after LAIV, 13 of 168 (8%) children reported some wheezing, with the vast majority, 9 of 13 (69%), on the day of vaccination.
  
  
  CONCLUSIONS
  There was no increased risk of respiratory deterioration or all-cause hospitalization associated with LAIV in our study population. LAIV seems well tolerated in children and adolescents with CF.
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada;
authors.forename: Constantina
authors.initials: C
authors.lastname: Boikos
authors.affiliation: Department of Social and Preventive Medicine, Laval University, Quebec City, Canada; Institut national de santé publique du Québec, Quebec, Canada;
authors.forename: Gaston
authors.initials: G
authors.lastname: De Serres
authors.affiliation: Divisions of Respiratory Medicine, and.
authors.forename: Larry C
authors.initials: LC
authors.lastname: Lands
authors.affiliation: Divisions of Infectious Diseases, and.
authors.forename: François D
authors.initials: FD
authors.lastname: Boucher
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, CHU Sainte-Justine, Montreal, Canada; and.
authors.forename: Bruce
authors.initials: B
authors.lastname: Tapiéro
authors.affiliation: Respiratory Medicine, Department of Pediatrics, Centre Mère-Enfant Soleil du CHU de Québec, Quebec, Canada;
authors.forename: Patrick
authors.initials: P
authors.lastname: Daigneault
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada; Institut national de santé publique du Québec, Quebec, Canada; Infectious Diseases, Department of Pediatrics, The Montreal Children's Hospital, McGill University, Montreal, Canada; McGill University Health Centre, Vaccine Study Centre, Research Institute of the MUHC, Montreal, Canada caroline.quach@mcgill.ca.
authors.forename: Caroline
authors.initials: C
authors.lastname: Quach
mesh_terms: D000281:Administration, Intranasal; D000293:Adolescent; D018771:Arthralgia / Q000139:chemically induced / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000453:epidemiology*; D005221:Fatigue / Q000139:chemically induced / Q000175:diagnosis; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000209:etiology; D014611:Vaccination / Q000009:adverse effects*
chemical_list: D007252:Influenza Vaccines
keywords: childhood vaccination; cystic fibrosis; influenza; live-attenuated influenza virus vaccine; vaccine; vaccine safety