Disease spread and control sim
Run a model class of 100 people day by day, set the vaccination slider and drag hand washing, masks and isolation into the rules tray, then compare the infection curves, peaks and totals of your runs and see herd immunity protect unvaccinated people.
Transmissible disease: how a pathogen spreads through a group, and how vaccination, hand washing, masks and isolation control it · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Disease spread and control: a model. 100 model people stand for one class. 2 people bring in an influenza-like virus on day 0. It spreads by droplets (coughs, sneezes, breathing out) and on hands (touch, then the face). Pneumococcus, a bacterium, also spreads by droplets, and the same controls cut its spread; antibiotics can treat bacterial infections, but not viral ones such as influenza. Press Next day: on each day every infectious person meets a fixed set of contacts (the up to 8 people around them, and 1 to 5 friends elsewhere in the room), and each contact who can still catch it has a small chance of catching it by droplets and a small chance by hands. Set the controls before or during a run. A vaccine contains pathogens that are dead, or weakened so they cannot cause disease; the body makes antibodies and memory cells, so a vaccinated person is immune. Vaccination % (slider): that share of people is vaccinated before day 1 and starts immune, so they cannot catch it or pass it on. Hand washing (soap pump in the tray): the hands chance is cut to ≈ 50 % of what it was. Masks (box of masks in the tray): the droplet chance is cut to ≈ 50 %. Isolation (stay-home house in the tray): people with symptoms stay home and make no contacts. A person who catches it is infectious from day 1 to day 5 after, has symptoms from day 2 (if they get any), and has recovered and is immune from day 6. Simplified on purpose: an illustrative model, not a forecast; one closed group of 100 people, nobody comes or goes; fixed contact patterns, the same every day; immunity (after recovery or vaccination) lasts the whole run; the vaccine works fully, for everyone vaccinated; the effect sizes are illustrative (≈); about 1 in 3 people never show symptoms; everyone with symptoms isolates at once and fully when isolation is on; everyone follows the controls that are on; the luck is fixed (seeded), so a run with the same settings always gives the same result; a control changed part-way through a run starts the next day; the vaccination % is set before day 1 only; the model does not show how ill anyone feels; real outbreaks vary widely.
- Lit ring: where to drop a control to switch it on
- Seating plan: the same 100 people, seen from above
- Bands on a person: none susceptible, three infected, two recovered, one vaccinated
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
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