SEIR+SD epidemic model

This model is an Insight Maker adaptation of the Stella one found at

https://exchange.iseesystems.com/public/michaelldeaton/covid-19-model-intro/index.html#page1

That demonstration model was well explained and documented.

That model used variables for the US situation where social distancing (sd) was announced 62 days after the first case of Covid-19 was reported and involved only moderately aggressive measures.

This model uses an initial population of 1 million people.  The values of variables used in the Stella model are used as defaults here except Ro is set to 2.5. This and other variables can be changed using sliders.

For example, set the "intensity of social distancing measures" slider to 0 to run the model without sd.

The default values are

fatality fraction = 0.016

incubation period = 3 days

intensity of sd measures = 0.4

fraction of sd participation = 0.55

delay before announcing sd measures (UK) = 46 days

disease duration = 7 days

Ro = 2.5