title: Risk of narcolepsy associated with inactivated adjuvanted (AS03) A/H1N1 (2009) pandemic influenza vaccine in Quebec.
abstract: BACKGROUND
  An association between an adjuvanted (AS03) A/H1N1 pandemic vaccine and narcolepsy has been reported in Europe.
  
  
  OBJECTIVE
  To assess narcolepsy risk following administration of a similar vaccine in Quebec.
  
  
  METHODS
  Retrospective population-based study.
  
  
  METHODS
  Neurologists and lung specialists in the province were invited to report narcolepsy cases to a single reference centre.
  
  
  METHODS
  Patients were interviewed by two sleep experts and standard diagnostic tests were performed. Immunization status was verified in the provincial pandemic influenza vaccination registry.
  
  
  METHODS
  Confirmed narcolepsy with or without cataplexy with onset of excessive daytime sleepiness between January 1st, 2009, and December 31st, 2010. Relative risks (RRs) were calculated using a Poisson model in a cohort analysis, by a self-controlled case series (SCCS) and a case-control method.
  
  
  RESULTS
  A total of 24 cases were included and overall incidence rate was 1.5 per million person-years. A cluster of 7 cases was observed among vaccinated persons in the winter 2009-2010. In the primary cohort analysis, 16-week post-vaccination RR was 4.32 (95% CI: 1.50-11.12). RR was 2.07 (0.70-6.17) in the SCCS, and 1.48 (0.37-7.03) using the case-control method. Estimates were lower when observation was restricted to the period of pandemic influenza circulation, and tended to be higher in persons <20 years old and for cataplexy cases.
  
  
  CONCLUSIONS
  Results are compatible with an excess risk of approximately one case per million vaccine doses, mainly in persons less than 20 years of age. However, a confounding effect of the influenza infection cannot be ruled out.
authors.affiliation: Centre for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur, and Department of Psychiatry, University of Montreal, Montreal, Canada.
authors.forename: Jacques
authors.initials: J
authors.lastname: Montplaisir
authors.affiliation: Centre for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur, Montreal, Canada.
authors.forename: Dominique
authors.initials: D
authors.lastname: Petit
authors.affiliation: Centre for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur, Montreal, Canada.
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Quinn
authors.affiliation: Quebec National Public Health Institute (Institut national de santé publique du Québec), Quebec City, Canada.
authors.forename: Manale
authors.initials: M
authors.lastname: Ouakki
authors.affiliation: Quebec University Hospital Research Centre, Quebec City, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Deceuninck
authors.affiliation: Centre for Advanced Research in Sleep Medicine, Hôpital du Sacré-Coeur, and Department of Medicine, University of Montreal, Montreal, Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Desautels
authors.affiliation: Stanford Center for Sleep Sciences and Medicine, Stanford University of Medicine, Palo Alto, CA, United States of America.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Mignot
authors.affiliation: Department of Social and Preventive Medicine, Laval University, Quebec City, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: De Wals
mesh_terms: D000276:Adjuvants, Immunologic / Q000009:adverse effects*; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D004338:Drug Combinations; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000009:adverse effects* / Q000627:therapeutic use; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000453:epidemiology*; D011136:Polysorbates / Q000009:adverse effects* / Q000627:therapeutic use; D011792:Quebec / Q000453:epidemiology; D012189:Retrospective Studies; D013185:Squalene / Q000009:adverse effects* / Q000627:therapeutic use; D014611:Vaccination; D055815:Young Adult; D024502:alpha-Tocopherol / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000276:Adjuvants, Immunologic; D004338:Drug Combinations; D007252:Influenza Vaccines; D011136:Polysorbates; D013185:Squalene; C550253:AS03 adjuvant; D024502:alpha-Tocopherol