Author: Simon Frost @sdwfrost
Simple models (see e.g. the standard SIR model) assume that individuals transition from infectious to recovered at a constant rate, such that the distribution of infectious periods follows an exponential distribution. For many infectious, this is an unrealistic assumption, and the distribution of infectious periods has a smaller variance than the exponential.
A number of approaches can be used to incorporate non-exponential distributions in deterministic epidemic models.
- The method of stages
- Partial differential equation models
- Integral equation models
For stochastic models, the method of stages can also be used. Alternatively, discrete-event simulation offers a simpler approach to implement these models, although at greater computational expense.