Intervention models
Epidemic interventions alter one or more biological or behavioural processes represented in a transmission model.
Changing transmission
Contact reduction or other transmission-reducing measures can be represented by a time-dependent parameter
\[\beta=\beta(t).\]A piecewise model may use different values before and after an intervention time.
Other mechanisms
Testing and isolation may shorten effective infectious duration, vaccination may reduce susceptibility or disease progression, and treatment may change recovery or mortality rates.
Comparison of scenarios
Models can compare intervention timing, strength and duration using outcomes such as epidemic size, peak prevalence or hospital demand.
Key idea. An intervention should modify the particular model mechanism that the real intervention is intended to affect.