Using a Nonlinear Mixed Effects Model to Estimate Anthrax Antibody Longevity and Decay

• Activity Number: 684
• Type: Contributed
• Date/Time: Thursday, August 5, 2010 : 10:30 AM to 12:20 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Lydia S.D. Foster*+ and Charles E. Rose, Jr. and Conrad Quinn
• Companies: Atlanta Research and Education Foundation and CDC and CDC
• Keywords: Non-Linear Mixed Effects Model ; Anthrax Vaccine Adsorbed (AVA) ; Antibody Longevity and Decay

Abstract

The long-term duration of antibodies from the licensed anthrax vaccine in the US (Anthrax Vaccine Adsorbed (AVA), BioThrax) is unknown. To estimate antibody longevity and decay, a non-linear mixed effects model was developed using data from the Centers for Disease Control and Prevention (CDC) Phase 4 human clinical trial. Anti-PA IgG concentrations were measured using ELISA for 1735 samples from 224 human subjects enrolled in the CDC 4IM treatment group (0, 1, 6 month intramuscular vaccine priming schedule and 42 month booster). We modeled the anti-PA IgG concentrations decay for the 36 month span between the last priming dose and the 42 month booster. Our model was used to predict and quantify the density for the duration of measurable anthrax antibodies for each of the 224 subjects. Potential research implications include optimizing vaccine supply in the event of a bioterrorist attack.