- 1Research Fellow, Public Health England, London, UK.
- 2Senior Statistician, Public Health England, London, UK.
- 3Consultant Physician, Guy’s and St Thomas’ NHS Trust, London, UK.
- 4Consultant Neurologist, Royal Hallamshire Hospital, Sheffield, UK.
- 5Consultant Neurologist, National Hospital for Neurology and Neurosurgery, London, UK.
- 6Consultant in Anaesthesia, Intensive Care and Sleep Disorders Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK.
- 7Consultant Neurologist/Clinical Lead – Sleep, Guy’s and St Thomas’ NHS Trust, London, UK.
- 8Consultant Neurologist, South Tees NHS Trust, Middlesborough, UK.
- 9Consultant Physician, Papworth Hospital NHS Foundation, Cambridge, UK.
- 10Pharmacoepidemiology Research and Intelligence Unit, Medicines and Healthcare Products Regulatory Agency, UK.
- 11Consultant Epidemiologist, Public Health England, London, UK.
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.
© 2016 Associated Professional Sleep Societies, LLC.
Pandemrix; adult; case-coverage; narcolepsy; vaccination