Extend previously approved access at CSDR (Research Proposal 12163): Novel approaches to the modelling of protective efficacy, immunity and infectious disease incidence: Malaria vaccination

Conventionally, estimation of vaccine efficacy uses data on first disease episode only and it uses data from 2 to 4 weeks after completion of vaccination only. Furthermore, it is often separated from analysis of immunogenicity. Since the WHO Malaria Vaccine Advisory Committee's call in 2008 for methodological research to improve estimation of vaccine efficacy, there has been improvement in the methodology but room to improve remains. We are developing a series of statistical models to enhance estimation of vaccine efficacy. Our methodological research include: - Models of non-linear trajectory of vaccine efficacy, using all disease episode data either from the date of first dose or from post-completion of primary vaccination series, and include antibody data around the time of vaccination to predict/personalize the trajectory. - Joint modelling of antibody and disease episodes over time to enhance understanding of their relationship and improve the estimation of efficacy. - Models of the dynamics between history of disease episodes and present/future disease incidence and how it modifies vaccine efficacy. - Compare different approaches for evaluation of correlates of protection, both at the person-level and site-level. We propose to use data from two malaria vaccine trials to: - Illustrate and compare the statistical models, and - Generate model parameters for setting up realistic computer simulations. Both trials included antibody and multiple disease episodes data. One trial included multiple study sites. So they are suitable for our purpose.