Comprehensive Glossary for Infectious Disease Modelling

Introduction

In the current literature, there is considerable heterogeneity in common terms related to infectious disease epidemiology and modelling. Furthermore, definitions of these terms are not often provided in research papers. This glossary presents a comprehensive list of terms and their definitions to unify the use and interpretation of infectious disease epidemiology and modelling terminology. Although the most frequently used definitions were included in this glossary, researchers may have alternative definitions for certain terms in the context of their research. Therefore, it is recommended that the readers first check for definitions provided by the authors when reading infectious disease mathematical modelling publications.

Filters

Agent‐based model

Types of mathematical models

Individuals in the model are described as discrete entities with their own characteristics. Also see individual-based model/micro-simulation model.

Used to describe host-pathogen interactions (compare Within-host model).

Compartmental model

Types of mathematical models

Population is divided into different compartments, such as different health or epidemiological states, to describe the mechanism of a dynamic epidemic. Compartmental models can be employed to estimate quantities such as basic Reproduction Number, prevalence, and incidence of a disease.

Example:
S-I-R-S model: The following Susceptible-Infectious-Recovered-Susceptible (SIRS) model can be used when the immunity conferred after disease is not permanent; a recovered individual becomes susceptible to infection again after a period of time.

Continuous‐time model

Types of mathematical models
A Dynamic model in which time is a continuous variable (in contrast to discrete-time model) and variables or outcomes can be estimated at any time point.
Interval of time used in discrete-time models (e.g., days, weeks, months, years).

Data‐driven model

Types of mathematical models
Based on data and not on existing knowledge/assumptions (i.e., theory) (compare theory-driven model).
In contrast to predictive models, descriptive models describe observations (e.g., effectiveness of past interventions).

Deterministic model

Types of mathematical models
The average measure (e.g., rates) of a system (e.g., populations) is described without randomness; in other words, the outcome is fixed (compare Stochastic model).

Discrete‐time model

Types of mathematical models
A type of Dynamic model which treats time as a discrete variable (i.e., a variable with finite number of values) in contrast to the continuous-time model; in a discrete-time model, other variables or outcomes can only change at specific time points.
Involves at least one time-varying variable.