User interface of 4Flu


4Flu comes with a user interface which allows to change nearly all simulation parameters. The user can explore different scenarios and save interesting parameter constellations to a file which can later be loaded to re-run these simulations. While the simulation runs, summary curves and tables are displayed and continuously updated on the user interface.

User interface of 4Flu

General structure

The user interface of 4Flu basically consists of a left side, where parameter values and other settings can be changed, a right hand side where results are displayed during the simulation in form of curves and tables, and a bottom where some steering elements are found. Many of the features of the user interface can be customized (see below for details). Click on the symbol (i) which is found in the upper right corner of each parameter box to show or hide specific help messages.

Left side: input

Sreenshot of parameter input Parameter settings and drop-down menus are found on the left hand side of the simulation tool, organized in:
  • Basic Settings
    • Simulation periods
    • Basic settings
    • Risk groups
    • Transmission
    • Natural history
    • Drift variants
  • Immunity
    • Initialisation
    • Mean duration of immunity
    • Cross protection
    • Interferon
    • Vaccine properties
    • Vaccine efficacy
  • Vaccination
    • Vaccination schedule
    • Vaccination coverage during the initialisation phase
    • Vaccination coverage during the evaluation phase: scenario 1
    • Vaccination coverage during the evaluation phase: scenario 2
Simulation output is given as graphs and tables, found on the right hand side of the simulation tool, and organized in:
  • Weekly incidence (of infections, displayed by vaccination strategy, influenza variant, and by age groups)
  • Cumulative (number of infections, displayed by vaccination strategy, influenza variant, and by age groups)
  • Vaccination (cumulative number of vaccinations, displayed by vaccination strategy, and by age groups)
  • SIR (infection and immunity status of the population, displayed by vaccination strategy, influenza variant, and by age groups)
  • Population (number of individuals, displayed by age groups)
  • Drift (annual composition of trivalent vaccine, occurrence of drift variants, and vaccine mismatch)
  • Infection Probability (visualization of seasonal fluctuation of the transmission probability)
  • Risk (diagnostic graph to visualize the simulated percentages of risk groups)

Bottom: steering elements

Buttons on the lower side of the 4Flu user interface are:
  • About 4Flu (displays the current version of 4Flu and important legal information)
  • Load (allows to load and re-run saved parameter constellations; please make sure that the file ending ".4flu" is included in the file name)
  • Save (allows to save the current parameter constellation to a file)
  • Export: saves the daily number of infections in vaccination scenario 1 and 2, respectively, by year of age and risk status (0 = "low risk") for each year of the evaluation period
  • Default (set all parameter values back to their default values)
  • Run (press this button to start a new simulation). In order to obtain a different random number sequence, please change "Initial random number" in Parameter tabulator "Basic settings", box "Basic settings"
  • The progress bar (bottom left) displays the message "update needed" if parameters have been changed. During a running simulation, it shows the progress of the simulation


Customize screen. How to change sections of the user interface You can change the percentage of the 4Flu user interface which is used for the input by pulling the selection line (highlighted in red in the figure on the right). Likewise, you can change the percentage of the output side which is used for the graph.

Further customizations, save or print pictures. Click into any output graph using the right mouse button to save or print your graph or to explore further possibilities to customize your output graphs:
  • Properties...
  • Copy
  • Save as...
  • Print...
  • Zoom In
  • Zoom Out
  • Auto Range
Zoom in. You can enlarge sections of the curve by selecting a section of these curves (see figure below). To do so, you have to click into the graph (left mouse button), pull up a rectangle from top left to bottom right, and then release the mouse button. This process can be repeated for several times to continue zooming into the curves. The labels of the vertical and horizontal axes will adjust automatically.
Zoom in
Zoom out. To get back to the original graph, you have to click into the graph and pull up a rectangle in the opposite direction, i.e. from bottom right to top left. This will completely restore the original picture. Going back stepwise is only possible by clicking into the graph with the left mouse button and selecting "Zoom Out".