PPolySim OS
Biology & Aerospace Pack · Multi-Solver

Vaccine Strategy

Herd immunity & rollout. This multi-solver chains 2 solvers into a single guided workflow — run each step in order and carry the result forward.

Workflow steps
  1. sir-model
  2. epidemic-network
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SIR Epidemic ModelLive

Controls

Presets

The SIR model splits a population into Susceptible, Infected, and Recovered and lets them flow between compartments. R₀ — the average number infected by one case — sets whether an outbreak grows. Vaccinating above the herd-immunity threshold 1−1/R₀ prevents an epidemic outright.

▶ Run in Python

Data Inspector

Peak infected0.0%
Total infected0.0%
Herd immunity60%

Governing equation

Reading this result: R₀ = 2.50 > 1 with only 0% immune, so infections grow into an epidemic. You would need to immunize 60% (the herd-immunity threshold 1−1/R₀) to stop it; the current effective reproduction number is 2.50.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

2

Epidemic Network

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Epidemic on a NetworkLive

Controls

Infection spreads along the contact network (red = infected, blue = susceptible, green = recovered). Tune transmission, recovery, and connectivity.

Presets

▶ Run in Python

Data Inspector

Susceptible0
Infected0
Recovered0
Edges0

Governing equation

Reading this result: Spread outpaces recovery by 6.0-to-1 — an epidemic grows, but whether it reaches everyone hinges on the contact radius wiring nodes together.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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More in the Biology & Aerospace pack

Frequently asked questions

What is the Vaccine Strategy multi-solver?
Vaccine Strategy is a guided workflow that chains 2 individual PolySim solvers into one end-to-end analysis, piping each result into the next step.
Is it free to use?
Yes. Every step runs entirely in your browser using real numerics — no install, no account, no cloud cost. Custom or private solver packs are available as a paid service.