Testing antibody dynamics models by parametric fitting of data

Abstract

Though several vaccines are believed to confer lifelong immunity, the fact that post vaccination antibodies naturally decay with time raises a debate on the true window of protection. In this respect, studies that monitor the persistence of post vaccination antibodies over time have been proposed. This work considers 289 healthy adults vaccinated for hepatitis A with the HavrixTM 1440 vaccine and followed up for at most 126 months. Several studies have mathematically modeled antibody decay after vaccination to predict long-term immunity. But not many have accounted for the biological dynamics of antibody persistence and/or inter-patient variability. This study aimed at developing simple mathematical models to account for the circulating anti-HAV antibodies, as well as antibody producing cells to study the evolution of post boosting antibodies, and to progress to test the plausibility of the underlying assumptions by parametric fitting of the data. Nonlinear mixed effects models provide