Showing papers by "M. Elizabeth Halloran published in 1993"
TL;DR: A stochastic epidemic model is formulated for the study of the protective effects of vaccination in a population that is stratified by vaccine-related factors and martingale-based methods are used to provide estimators of vaccine efficacy and their variances.
Abstract: A stochastic model is formulated for the study of the protective effects of vaccination in a population that is stratified by vaccine-related factors. The epidemic model is transformed into a counting process, and then martingale-based methods are used to provide estimators of vaccine efficacy and their variances. following an example, various extensions of the model are discussed.
26 citations
TL;DR: Using the time-evolving information for the aggregated vaccinated cohort and the unvaccinated cohort, it is possible to reconstruct the distribution of effective protection imparted by the vaccination at the beginning of observation.
Abstract: We assume that individuals in a vaccinated cohort respond heterogeneously and acquire a continuous spectrum of effective protection against an environmental exposure to infection that can be varying in time. The notion of dynamical invariants is applied to a proportional hazard model with an unvaccinated or placebo cohort as baseline. The hazard is expressed as a susceptibility factor times a measure of environmental exposure to infection. Using the time-evolving information for the aggregated vaccinated cohort and the unvaccinated cohort, it is possible to reconstruct the distribution of effective protection imparted by the vaccination at the beginning of observation. Efficacy is defined in terms of the hazard ratio at the beginning of observation.
23 citations