title: Encephalitis temporally associated with live attenuated Japanese encephalitis vaccine: four case reports.
abstract: BACKGROUND
  Japanese encephalitis (JE) vaccination is the most effective measure for preventing JE disease. The live attenuated JE vaccine, which has shown good efficacy and safety, has been widely used in China.
  
  
  METHODS
  We report four laboratory-confirmed JE cases detected in JE-endemic areas during the JE virus (JEV) transmission season, who all received a first dose of live attenuated JE vaccine within 2 weeks prior to the onset of illness. All cases presented with acute encephalitis and rapidly reduced consciousness. All cerebrospinal fluid (CSF) samples from the patients were positive for JEV-specific immunoglobulin M (IgM) antibodies, but viral isolation and polymerase chain reaction (PCR) detection of JEV were both negative.
  
  
  CONCLUSIONS
  It is difficult to identify a causal link between the disease and the vaccination, as the source of positive CSF JEV IgM antibodies might be natural JEV infection or possibly due to a traumatic lumbar puncture. Our observations highlight the need for public health officers and doctors to consider reasonable vaccination policies during the JE season. In addition, continued surveillance as well as thorough investigation of any events that occur after JE vaccination is necessary.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong Da-Street, Fengtai District, Beijing 100071, People's Republic of China.
authors.forename: Na
authors.initials: N
authors.lastname: Jia
authors.forename: Qiu-Min
authors.initials: QM
authors.lastname: Zhao
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Guo
authors.forename: Jing-Xia
authors.initials: JX
authors.lastname: Cheng
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.forename: Shu-Qing
authors.initials: SQ
authors.lastname: Zuo
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Dai
authors.forename: Jun-Ying
authors.initials: JY
authors.lastname: Zhao
authors.forename: Jiu-Song
authors.initials: JS
authors.lastname: Zhang
mesh_terms: D000914:Antibodies, Viral / Q000134:cerebrospinal fluid; D002675:Child, Preschool; D002681:China; D004664:Encephalitis Virus, Japanese / Q000302:isolation & purification; D004672:Encephalitis, Japanese / Q000134:cerebrospinal fluid / Q000209:etiology* / Q000276:immunology; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000134:cerebrospinal fluid; D007223:Infant; D022321:Japanese Encephalitis Vaccines / Q000009:adverse effects*; D008297:Male; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral; D007075:Immunoglobulin M; D022321:Japanese Encephalitis Vaccines