Epidemic Spread Simulator
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Infection Curve (SIR Model)
Days
Population %
100
50
0
Population Grid (n=100)
Susceptible
Infected
Recovered
Vaccinated
2.5
R₀ (basic)
1.8
Rₑ (effective)
Day 12
Peak infection
85%
Final attack rate
R₀ (contagiousness)
2.5
0.5
6.0
Infectious period (days)
8
3
21
Vaccination coverage
0%
0%
95%
With
R₀ = 2.5
and no vaccination, each infected person infects 2.5 others on average. The epidemic grows until enough people are immune (herd immunity threshold ≈
60%
) that transmission can no longer sustain itself.