title: Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity.
abstract: We describe the Bacillus anthracis protective antigen IgG antibody response and the B. anthracis lethal toxin neutralization activity to a delayed dose of anthrax vaccine adsorbed (AVA, BioThrax(®)) using validated assays. 373 individuals received 1, 2, or 3 priming doses, 18-24 months afterward, they received a delayed dose of AVA. Overall, 23.6% of subjects showed detectable anti-PA IgG before the boost, compared to 99.2% (P<0.0001) 28 days after the boost. Geometric mean anti-PA IgG concentration (GMC) was 1.66 μg/mL before and 887.82 μg/mL after the boost (P<0.0001). The proportion of individuals with four-fold increase in GMC following the boost ranged from 93.8% to 100%. Robust anti-PA IgG levels and B. anthracis lethal toxin neutralization activity are induced when an AVA dose is delayed as long as two years. These data support continuing with the vaccination schedule when a dose is delayed as long as two years rather than restarting the series.
authors.affiliation: Department of Clinical Research, U. S. Army Medical Research of Infectious Diseases (USAMRIID), Fort Detrick, MD, USA. Electronic address: phillip.r.pittman.civ@mail.mil.
authors.forename: Phillip R
authors.initials: PR
authors.lastname: Pittman
authors.forename: Diana
authors.initials: D
authors.lastname: Fisher
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Quinn
authors.forename: Trevor
authors.initials: T
authors.lastname: Schmader
authors.forename: Julio G
authors.initials: JG
authors.lastname: Barrera-Oro
mesh_terms: D000328:Adult; D000881:Anthrax / Q000276:immunology* / Q000517:prevention & control; D022122:Anthrax Vaccines / Q000008:administration & dosage / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000276:immunology*; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D055815:Young Adult
chemical_list: D022122:Anthrax Vaccines; D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; C493276:Biothrax; D007074:Immunoglobulin G; C030325:anthrax toxin
keywords: AVA; BioThrax(®) anthrax vaccine adsorbed; Human antibody response to anthrax vaccine