title: Immunogenicity of one dose of Vero cell culture-derived Japanese encephalitis (JE) vaccine in adults previously vaccinated with mouse brain-derived JE vaccine.
abstract: BACKGROUND
  There are no data on the use of inactivated Vero cell culture-derived Japanese encephalitis (JE) vaccine (JE-VC) as a booster among individuals who previously received inactivated mouse brain-derived JE vaccine (JE-MB).
  
  
  METHODS
  Military personnel who received ≥3 doses of JE-MB or were JE vaccine-naïve were vaccinated with 2 doses of JE-VC on days 0 and 28. Serum neutralizing antibodies were measured pre-vaccination and 28 days after each dose. Non-inferiority was evaluated for seroprotection rate and geometric mean titer (GMT) between previously vaccinated participants post-dose 1 and vaccine-naïve participants post-dose 2.
  
  
  RESULTS
  Fifty-three previously vaccinated and 70 JE vaccine-naïve participants were enrolled. Previously vaccinated participants had significantly higher GMTs pre-vaccination, post-dose 1, and post-dose 2. Seroprotection rates among previously vaccinated participants post-dose 1 (44/44, 100%) were noninferior to those achieved in previously naïve participants post-dose 2 (53/57, 93%). The GMT was significantly higher in previously vaccinated participants post-dose 1 (GMT 315; 95% CI 191-520) compared to previously naïve participants post-dose 2 (GMT 79; 95% CI 54-114).
  
  
  CONCLUSIONS
  Among military personnel previously vaccinated with ≥3 doses of JE-MB, a single dose of JE-VC adequately boosts neutralizing antibody levels and provides at least short-term protection. Additional studies are needed to confirm these findings in other populations and determine the duration of protection following a single dose of JE-VC in prior recipients of JE-MB.
authors.affiliation: Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA.
authors.forename: Tabitha
authors.initials: T
authors.lastname: Woolpert
authors.forename: J Erin
authors.initials: JE
authors.lastname: Staples
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Faix
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Nett
authors.forename: Olga I
authors.initials: OI
authors.lastname: Kosoy
authors.forename: Brad J
authors.initials: BJ
authors.lastname: Biggerstaff
authors.forename: Barbara W
authors.initials: BW
authors.lastname: Johnson
authors.forename: Michael
authors.initials: M
authors.lastname: Sracic
authors.forename: Marc
authors.initials: M
authors.lastname: Fischer
mesh_terms: D000328:Adult; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001921:Brain / Q000821:virology; D002522:Chlorocebus aethiops; D004672:Encephalitis, Japanese / Q000517:prevention & control*; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D022321:Japanese Encephalitis Vaccines / Q000008:administration & dosage / Q000276:immunology*; D051379:Mice; D008889:Military Personnel; D013678:Technology, Pharmaceutical / Q000379:methods*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014709:Vero Cells
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D022321:Japanese Encephalitis Vaccines; D015164:Vaccines, Inactivated