This JAVA applet allows to visualize the spread of infection in a population according to the classical SIR model.
Disclaimer:
In no event, shall the University to Tübingen, or any person be liable for any loss, expense or damage, of any type or nature arising out of the use of, or inability to use this program, including, but not limited to, claims or suits.
(uses JAVA)
Explanation of parameters
Immune Fraction
Fraction of the population which is immune at the beginning of the simulation (e. g. because of earlier vaccination or of previous outbreaks)
Exposed Fraction
Fraction of the population which is infected at the beginning of the simulation (it is assumed that these individuals were infected at the start of the simulation - they will become infectious to athers after the end of their latent period)
Basic reproduction number
Average number of secondary infections caused by one index case in a completely susceptible (non-immune) population where no interventions are performed
Rate latent -> infectious
Rate at which newly infected individuals become infectious (because of the implicit assumption of exponential sojourn times, the average duration of this waiting time is given by the fraction "one over this rate")
Rate infectious -> immune
rate at which infectious individuals lose their infectiousness and become immune (because of the implicit assumption of exponential sojourn times, the average infectious duration is given by the fraction "one over this rate")
Rate immune -> susceptible
Rate at which immune individuals lose their immunity and become susceptible again (because of the implicit assumption of exponential sojourn times, the average duration of immunity is given by the fraction "one over this rate")
If this rate is bigger than zero, the model is strictly speaking no longer an SIR model but the SIRS model.
Mortality rate
Rate at which individuals die (because of the implicit assumption of exponential sojourn times, the average life expectancy is given by the fraction "one over this rate")
This rate only considers natural mortality - it is not considered here that individuals die because of the disease.
Vaccinated fraction
Vaccinated fracton of newborns.
As the initially immune fraction of the population has to be set with the slider mentioned above, this one will only show action during the course of the outbreak.
Graphics
Size of figure and table
Moving around the dotted horizontal and vertical bars in the applet will change the sizes of figure and table, respectively
Shorter and longer simulation periods
The horizontal axis below the figure can be stretched using the mouse
Vertical axis
... so can the vertical axis (e. g. to see more details of a curve which is close to zero)
Table
The table shows for each day and category the exact simulated numbers.
Use the scroll bar to move inside the table.
Eberhard-Karls-University Tübingen,
Tübingen University Hospital,
the Department for Medical Biometry (IMB),
and the authors of this page disclaim all liability for the content of any page referenced by hyper-link from this page
