title: Incidence of narcolepsy before and after MF59-adjuvanted influenza A(H1N1)pdm09 vaccination in South Korean soldiers.
abstract: BACKGROUND
  Previous reports mostly from Europe suggested an association between an occurrence of narcolepsy and an influenza A(H1N1)pdm09 vaccine adjuvanted with AS03 (Pandemrix(®)). During the 2009 H1N1 pandemic vaccination campaign, the Korean military performed a vaccination campaign with one type of influenza vaccine containing MF59-adjuvants. This study was conducted to investigate the background incidence rate of narcolepsy in South Korean soldiers and the association of the MF59-adjuvanted vaccine with the occurrence of narcolepsy in a young adult group.
  
  
  METHODS
  To assess the incidence of narcolepsy, we retrospectively reviewed medical records of suspicious cases of narcolepsy in 2007-2013 in the whole 20 military hospitals of the Korean military. The screened cases were classified according to the Brighton Collaboration case definition of narcolepsy. After obtaining the number of confirmed cases of narcolepsy per 3 months in 2007-2013, we compared the crude incidence rate of narcolepsy before and after the vaccination campaign.
  
  
  RESULTS
  We included 218 narcolepsy suspicious cases in the initial review, which were screened by the diagnostic code on the computerized disease registry in 2007-2013. Forty-one cases were finally diagnosed with narcolepsy in 2007-2013 (male sex, 95%; median age, 21 years). The average background incidence rate of narcolepsy in Korean soldiers was 0.91 cases per 100,000 persons per year. During the 9 months before vaccination implementation (April to December 2009), 6 narcolepsy cases occurred, whereas during the next 9 months (January to September 2010) including the 3-month vaccination campaign, 5 cases occurred.
  
  
  CONCLUSIONS
  The incidence of narcolepsy in South Korean soldiers was not increased after the pandemic vaccination campaign using the MF59-adjuvanted vaccine. Our results suggest that the MF59-adjuvanted H1N1 vaccine did not contribute to the occurrence of narcolepsy in this young adult group.
authors.affiliation: Department of Psychiatry, Eulji Addiction Institute, Gangnam Eulji Hospital, Eulji University, Seoul, South Korea; Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Woo Jung
authors.initials: WJ
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, The Armed Forces Capital Hospital, Seongnam, Gyeonggi, South Korea.
authors.forename: Sang Don
authors.initials: SD
authors.lastname: Lee
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, South Korea; Department of Psychiatry, Yonsei University College of Medicine, Seoul, South Korea; Sleep Health Center, Severance Hospital, Seoul, South Korea.
authors.forename: Eun
authors.initials: E
authors.lastname: Lee
authors.affiliation: Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, South Korea; Department of Psychiatry, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Kee
authors.initials: K
authors.lastname: Namkoong
authors.affiliation: Department of Internal Medicine, The Armed Forces Capital Hospital, Seongnam, Gyeonggi, South Korea.
authors.forename: Kang-Won
authors.initials: KW
authors.lastname: Choe
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.affiliation: Department of Internal Medicine, Chungbuk National University, Cheongju, Chungbuk, South Korea.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Jeong
authors.affiliation: Department of Internal Medicine, Chungbuk National University, Cheongju, Chungbuk, South Korea. Electronic address: jyeon78@naver.com.
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Heo
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000009:adverse effects*; D000328:Adult; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008889:Military Personnel; D009290:Narcolepsy / Q000139:chemically induced* / Q000453:epidemiology*; D011136:Polysorbates / Q000008:administration & dosage / Q000009:adverse effects*; D056910:Republic of Korea; D012189:Retrospective Studies; D013185:Squalene / Q000008:administration & dosage / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D007252:Influenza Vaccines; C089950:MF59 oil emulsion; D011136:Polysorbates; D013185:Squalene
keywords: Adjuvants; H1N1 influenza A; Incidence; MF59; Narcolepsy; Vaccination