title: Risk of Narcolepsy after AS03 Adjuvanted Pandemic A/H1N1 2009 Influenza Vaccine in Adults: A Case-Coverage Study in England.
abstract: An increased risk of narcolepsy has been observed in children following ASO3-adjuvanted pandemic A/H1N1 2009 (Pandemrix) vaccine. We investigated whether this risk extends to adults in England.
  
  
  
  Six adult sleep centers in England were visited between November 2012 and February 2014 and vaccination/clinical histories obtained from general practitioners. Suspected narcolepsy cases aged older than 17 y were selected. The risk of narcolepsy following Pandemrix was calculated using cases diagnosed by the time of the center visits and those with a diagnosis by November 30, 2011 after which there was increased awareness of the risk in children. The odds of vaccination in cases and in matched population data were compared using a case-coverage design.
  
  
  
  Of 1,446 possible cases identified, most had onset before 2009 or were clearly not narcolepsy. Of the 60 remaining cases, 20 were excluded after expert review, leaving 40 cases with narcolepsy; 5 had received Pandemrix between 3 and 18 mo before onset. All the vaccinated cases had cataplexy, two received a diagnosis by November 2011 and two were aged 40 y or older. The odds ratio for vaccination in cases compared to the population was 4.24 (95% confidence interval 1.45-12.38) using all cases and 9.06 (1.90-43.17) using cases with a diagnosis by November 2011, giving an attributable risk of 0.59 cases per 100,000 doses.
  
  
  
  We found a significantly increased risk of narcolepsy in adults following Pandemrix vaccination in England. The risk was lower than that seen in children using a similar study design.
authors: Research Fellow, Public Health England, London, UK.
authors: Julia
authors: J
authors: Stowe
authors: Senior Statistician, Public Health England, London, UK.
authors: Nicholas
authors: N
authors: Andrews
authors: Consultant Physician, Guy's and St Thomas' NHS Trust, London, UK.
authors: Christopher
authors: C
authors: Kosky
authors: Consultant Neurologist, Royal Hallamshire Hospital, Sheffield, UK.
authors: Gary
authors: G
authors: Dennis
authors: Consultant Neurologist, National Hospital for Neurology and Neurosurgery, London, UK.
authors: Sofia
authors: S
authors: Eriksson
authors: Consultant in Anaesthesia, Intensive Care and Sleep Disorders Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK.
authors: Andrew
authors: A
authors: Hall
authors: Consultant Neurologist/Clinical Lead - Sleep, Guy's and St Thomas' NHS Trust, London, UK.
authors: Guy
authors: G
authors: Leschziner
authors: Consultant Neurologist, South Tees NHS Trust, Middlesborough, UK.
authors: Paul
authors: P
authors: Reading
authors: Consultant Physician, Papworth Hospital NHS Foundation, Cambridge, UK.
authors: John M
authors: JM
authors: Shneerson
authors: Pharmacoepidemiology Research and Intelligence Unit, Medicines and Healthcare Products Regulatory Agency, UK.
authors: Katherine
authors: K
authors: Donegan
authors: Consultant Epidemiologist, Public Health England, London, UK.
authors: Elizabeth
authors: E
authors: Miller
mesh_terms: D000276:Adjuvants, Immunologic; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002385:Cataplexy / Q000175:diagnosis / Q000453:epidemiology; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis / Q000453:epidemiology*; D016017:Odds Ratio; D058873:Pandemics; D015203:Reproducibility of Results; D012107:Research Design; D018570:Risk Assessment; D012890:Sleep; D014611:Vaccination / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D007252:Influenza Vaccines; C556153:pandemrix
keywords: Pandemrix; adult; case-coverage; narcolepsy; vaccination