Clinical trials : the mathematics of falling vaccine efficacy with rising disease incidence

Gomes, M. Gabriela M. and Gordon, Stephen B. and Lalloo, David G. (2016) Clinical trials : the mathematics of falling vaccine efficacy with rising disease incidence. Vaccine, 34 (27). pp. 3007-3009. ISSN 0264-410X

[img]
Preview
Text (Gomes-etal-Vaccine-2016-the-mathematics-of-falling-vaccine-efficacy)
Gomes_etal_Vaccine_2016_the_mathematics_of_falling_vaccine_efficacy.pdf
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (356kB)| Preview

    Abstract

    Reports of unexplained discrepancies in the efficacy of vaccines, as estimated from randomised controlled trials in different parts of the world, are commonplace in the literature [1], [2], [3], [4]. Moreover, there is a consistent trend for lower vaccine efficacy when measured in settings where the disease of interest has a higher incidence, leading to questions about the appropriateness of pooled estimates. Here, we examine the mathematical basis for such trends and propose a measure of efficacy that is valid across settings. The approach relies on fitting mechanistic models, which specify pathogen exposures and host responses, to global vaccine trial data stratified by local disease incidence. Such models enable the estimation of vaccine protection per exposure to the pathogen. A strategy to estimate per-exposure vaccine efficacy will enable more accurate estimates of vaccine efficacy across a range of disease incidence [5].