Overview of Vaccine Effects and Study Designs

Abstract

In this chapter, we present a systematic framework showing the relation among many of the different vaccination effects and the parameters and study designs to estimate them. This framework provides a structure for thinking about the different vaccine effects of interest and how they are related to one another. We present different versions of vaccine efficacy and effectiveness as one minus some measure of relative risk, RR.

$$VE = 1 - RR.$$

We focus on the relation between the vaccine effects of interest and the choice of comparison groups, the unit of observation, the choice of parameter, and the amount of information about the transmission system required for estimation. The frame-work draws on the dependent happening relation in infectious diseases. Although the framework is not exhaustive, many designs not considered explicitly in this overview are special cases of these general designs. Our primary concern in this chapter is conceptual. Details of study design and methods of estimation and inference are left to following chapters.