Day 0

Click the map to stage a mass gathering with a few infectious attendees. Space = play/pause · R = reset.

ContagionAgent-based SEIR model with households, workplaces, cities and a hospital system

Playback

Seed

Compare with stored no-action baseline

R₀ measured (no action)…

R(t) now (current settings)…

R₀ is emergent. It comes from the contact rate (agents inside the contact range, hours spent together at home, work and venues) times transmissibility times infectious days. Change any of them and watch R(t) shift.
Flatten the curve. The orange line is hospital capacity. Where the magenta curve rises above it, care is overloaded and the death rate of patients rises. Compare the peak with the dashed no-action curve.
R(t) crossing 1 marks the epidemic peak. Lockdown pushes it below 1 fast, but lifting it can trigger a second wave.
Age matters. Deaths concentrate in the 65+ group. Vaccination helps most when it starts before the wave and reaches the old first.
Test and trace works only if enough cases are found and contacts quarantine. Heat view shows how clusters flare in cities and spread along travel routes.
A superspreader event seeds hundreds of contacts in a few hours, so one gathering can ignite a whole city.