Interactive Flu Spread Visualization

I developed this simulation as part of my work on the VaccineComm project. The aim is to explore how vaccination, infection risk, vaccine effectiveness, and potential vaccine side effects can be communicated interactively.

Open the interactive simulation

Distance-based transmission

Transmission probability decreases with distance. For an unvaccinated susceptible person:

P unvac = β d 2

where β is the baseline transmission probability and d is the distance between an infected and susceptible person.

For a vaccinated susceptible person:

P vac = β d 2 (1 - E)

where E is vaccine effectiveness. For example, if:

E = 0.50

then:

P vac = β d 2 (1 - 0.50)

At 100% effectiveness:

E = 1

P vac = β d 2 (1 - 1) = 0

A susceptible person may also receive exposure from multiple infected people during the same simulation step.

Spread bias

The simulation can apply a small 5% spread bias toward either the vaccinated or unvaccinated group.

Neutral

P unvac = β d 2

P vac = β d 2 (1 - E)

Toward vaccinated

Vaccine effectiveness is reduced by 5%:

E' = 0.95E

P vac = β d 2 (1 - 0.95E)

P unvac = β d 2 \times 0.95

If:

E = 0.50

then:

E' = 0.95 \times 0.50 = 0.475

Toward unvaccinated

Vaccine effectiveness is increased by 5%:

E' = min(1, 1.05E)

P vac = β d 2 (1 - E')

P unvac = β d 2 \times 1.05

If:

E = 0.50

then:

E' = 1.05 \times 0.50 = 0.525

Simulation settings

The user can change vaccination coverage, vaccine effectiveness, side-effect probability, target infections, visualization speed, spread bias, and whether the vaccinated group appears on the left or right.

All settings are fixed when Play is pressed. Changes made during a running simulation take effect only on the next run.

Purpose and limitations

This is an interactive visualization, not an epidemiological forecasting model. The distance-based transmission function and the 5% spread-bias adjustment are modeling choices for the visualization and should not be interpreted as real-world estimates of influenza transmission.