A Mixed-Effects Model to Estimate Duration of Antibody Responses to Anthrax Vaccine in Humans and Non-Human Primates

• Activity Number: 87
• Type: Contributed
• Date/Time: Sunday, July 31, 2011 : 4:00 PM to 5:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Charles Rose*+ and Lydia Foster and Conrad Quinn
• Companies: Centers for Disease Control and Prevention and Centers for Disease Control and Prevention and Centers for Disease Control and Prevention
• Keywords: Mixed Effects Model ; Anthrax Vaccine Adsorbed (AVA) ; Antibody Decay ; Correlate of Protection

Abstract

We investigated anti-protective antigen (PA) antibody concentrations and persistence characteristics in human and Rhesus macaque non-human primate (NHP) immune responses to the US licensed Anthrax Vaccine Adsorbed (AVA). Data were from the CDC Phase 4 human clinical trial and NHP correlates of protection study. Human data were 1735 observations from 224 subjects that received AVA as a 3-dose intramuscular (IM) priming series and a booster vaccination at month 42 (0, 1, 6, 42m). NHP data were 1343 observations from 23 unvaccinated and 114 vaccinated NHP that received AVA as a 3-dose IM priming series (0, 1, 6m) with no boosters. The magnitudes of NHP antibody responses were modulated using divided doses of AVA (dilution in sterile saline; undiluted AVA, 1/5, 1/10, 1/20,1/40). NHP were exposed to aerosolized Bacillus anthracis Ames spores at either week 52, 124 or 228 after the first vaccination; fatality was 32% (44/137). We used a mixed-effects model to estimate anti-PA antibody persistence for the 36m span between the last priming dose and the 42m booster. Estimates of the antibody response and rate of decline were compared among the human and NHP groups.