Study objectives: Following the 2009 pandemic, reports of an association between an AS03 adjuvanted H1N1 pandemic influenza vaccine and narcolepsy were published. Besides determining background incidence rates for narcolepsy in Germany this study aimed at investigating whether there was a change in incidence rates of narcolepsy between the pre-pandemic, pandemic, and the post-pandemic period on the population level.
Design: Retrospective epidemiological study on the incidence of narcolepsy with additional capture-recapture analysis.
Setting: German sleep centers.
Patients or participants: Eligible were patients with an initial diagnosis of narcolepsy (ICD10 Code G47.4) within the period from January 1, 2007 to December 31, 2011.
Interventions: None; observational study.
Measurements and results: A total of 342 sleep centers were invited to participate in the study. Adequate and suitable data were provided by 233 sleep centers (68.1%). A total of 1,198 patients with an initial diagnosis of narcolepsy within the observed period were included, of whom 106 (8.8%) were children and adolescents under the age of 18 years and 1,092 (91.2%) were adults. In children and adolescents, the age-standardized adjusted incidence rate significantly increased from 0.14/100,000 person-years in the pre-pandemic period to 0.50/100,000 person-years in the post-pandemic period (incidence density ratio, IDR 3.57; 95% CI 1.94-7.00). In adults, no significant change was detectable. This increase started in spring 2009.
Conclusions: For the years 2007-2011, valid estimates for the incidence of narcolepsy in Germany were provided. In individuals under 18, the incidence rates continuously increased from spring 2009.
Keywords: Germany; epidemiology; incidence; narcolepsy.
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