A sudden increase in narcolepsy in Finnish children at the beginning of 2010 was likely related to the Pandemrix vaccine used in response to the H1N1 2009 flu pandemic, according to two reports published Mar. 28 in the open access journal PLoS ONE.
The authors of the studies, led by Markku Partinen of the Helsinki Sleep Clinic and Hanna Nohynek of the National Institute for Health and Welfare in Finland, found that the average annual incidence of narcolepsy between 2002 and 2009 among children younger than 17 was 0.31 per 100,000, and in 2010, this incidence was about 17 times higher, at 5.3 cases per 100,000. In contrast, the incidence rate for adults over 20 was essentially unchanged over that same time period.
To further evaluate the potential connection between the vaccine and narcolepsy, the researchers collected vaccination and childhood narcolepsy data for children born between January 1991 and December 2005.
They found that the narcolepsy incidence for vaccinated individuals within this age group was 9.0 per 100,000 people, as compared to just 0.7 per 100,000 for unvaccinated individuals - almost 13 times lower.
Together, these results provide compelling evidence that the Pandemrix vaccine, used in 2009 and 2010 in association with the H1N1 flu pandemic, contributed to narcolepsy in patients between the age of 4 and 19 in Finland, the authors conclude.
Citation: Nohynek H, Jokinen J, Partinen M, Vaarala O, Kirjavainen T, et al. (2012) AS03 Adjuvanted AH1N1 Vaccine Associated with an Abrupt Increase in the Incidence of Childhood Narcolepsy in Finland. PLoS ONE 7(3): e33536. doi:10.1371/journal.pone.0033536
Citation: Partinen M, Saarenpa¨a¨-Heikkila¨ O, Ilveskoski I, Hublin C, Linna M, et al. (2012) Increased Incidence and Clinical Picture of Childhood Narcolepsy following the 2009 H1N1 Pandemic Vaccination Campaign in Finland. PLoS ONE 7(3): e33723. doi:10.1371/journal.pone.0033723
Financial Disclosure: The following organizations funded the study: National Institute for Health and Welfare (THL) and Ministry of Social Affairs and Health, Finland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Financial Disclosure: The authors have no external support or funding to report. The collection of data from the registries and from different hospitals was funded by THL. The study group had freedom for the study design, data collection, data analysis, data interpretation, and writing of the report. The authors had access to all the data, take responsibility for the integrity of the data and the accuracy of the analysis, and had final responsibility for the reporting of the data.
Competing Interest Statement: HN received honoraria for technical consultancy from GlaxoSmithKline (GSK), and Pfizer for development of pneumococcal conjugate vaccines. JJ is co-investigator of a nationwide effectiveness study of the ten-valent pneumococcal conjugate vaccine mainly funded by GlaxoSmithKline. MP has been consultant for Bioprojet and UCB Pharma and received funding support and travel grants from Boehringer-Ingelheim, Bioprojet, GSK, Cephalin, MSD, Leiras and Servier. T. Kilpi is principal investigator of a nationwide effectiveness study of the ten-valent pneumococcal conjugate vaccine mainly funded by GlaxoSmithKline, and her unit received funding for a clinical trial on the safety and immunogenicity of a prototype pandemic influenza vaccine from Solvay Pharmaceuticals. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials. All other authors confirm they have no conflicts of interest.
Competing Interest Statement: The authors have declared that no competing interests exist.
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