title: Immunogenicity and safety of four different dosing regimens of anthrax vaccine adsorbed for post-exposure prophylaxis for anthrax in adults.
abstract: BACKGROUND
  Strategies to implement post exposure prophylaxis (PEP) in case of an anthrax bioterror event are needed. To increase the number of doses of vaccine available we evaluated reducing the amount of vaccine administered at each of the vaccinations, and reducing the number of doses administered.
  
  
  METHODS
  Healthy male and non-pregnant female subjects between the ages of 18 and 65 were enrolled and randomized 1:1:1:1 to one of four study arms to receive 0.5 mL (standard dose) of vaccine subcutaneously (SQ) at: (A) days 0, 14; (B) days 0 and 28; (C) days 0, 14, and 28; or (D) 0.25 mL at days 0, 14, and 28. A booster was provided on day 180. Safety was assessed after each dose. Blood was obtained on days 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 84, 100, 180, and 201 and both Toxin Neutralizing antibody and anti-PA IgG antibody measured.
  
  
  RESULTS
  Almost all subjects developed some local reactions with 46-64% reported to be of moderate severity and 3.3% severe during the primary series. Vaccine groups that included a day 14 dose induced a ≥ 4 fold antibody rise in more subjects on days 21, 28, and 35 than the arm without a day 14 dose. However, schedules with a full day 28 dose induced higher peak levels of antibody that persisted longer. The half dose regimen did not induce antibody as well as the full dose study arms.
  
  
  CONCLUSIONS
  Depending on the extent of the outbreak, effectiveness of antibiotics and availability of vaccine, the full dose 0, 28 or 0, 14, 28 schedules may have advantages.
authors.affiliation: Cincinnati Children's Hospital Medical Center, University of Cincinnati, 3333 Burnet Ave., Cincinnati, OH 45229, USA. Electronic address: david.bernstein@cchmc.org.
authors.forename: David I
authors.initials: DI
authors.lastname: Bernstein
authors.affiliation: Group Health Research Institute, Group Health Cooperative, Seattle, WA, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Jackson
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: Shital M
authors.initials: SM
authors.lastname: Patel
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: Hana M
authors.initials: HM
authors.lastname: El Sahly
authors.affiliation: Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Spearman
authors.affiliation: Hope Clinic of the Emory Vaccine Center, Atlanta, GA, USA.
authors.forename: Nadine
authors.initials: N
authors.lastname: Rouphael
authors.affiliation: Battelle Memorial Institute, Columbus, OH, USA.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Rudge
authors.affiliation: The EMMES Corporation, Rockville, MD, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Hill
authors.affiliation: The EMMES Corporation, Rockville, MD, USA.
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Goll
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000881:Anthrax / Q000517:prevention & control*; D022122:Anthrax Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood; D057134:Antibodies, Neutralizing / Q000097:blood; D005260:Female; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D056990:Post-Exposure Prophylaxis; D055815:Young Adult
chemical_list: D022122:Anthrax Vaccines; D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D007074:Immunoglobulin G
keywords: Anthrax; Post exposure prophylaxis; Vaccine