We present here the different parameters of this Shiny.

Mass screening

The model can incorporate the effect of mass screening on the spread of the epidemic. In practice, this option removes a proportion of the contagious individuals, who are assumed to be isolated.

If this option is activated, the date of start of the screening as well as the proportion of infectious individuals who can be isolated must be specified.

Adaptive lock down (“stop & go”)

This strategy consists in alterating between strict and relaxed control. The adaptativity comes from the fact that strict control is initiated when the daily number of ICU admissions exceeds a certain threshold, which must be specified by the user. The intensity of the strict control, i.e. the percentage of reduction in the reproduction number, must also be specified.

Control strategies

It is possible to implement control strategies over a variable number of time intervals with various intensities.

The control can also be applied differently depending on population age groups. If more than one age group is defined, the separation age must be specified (e.g. introducing 42 as a break point creates two groups, one with people below 42 and one with people above 42).

A control level must aslo be specified for each group.

Do not put twice the same age of separation!

Periodic control

While ad hoc control strategies are practical in the short term, in the long term having periodic strategies may facilitate planning.

These involve defining a periodicity for which different levels of control can be applied to different groups within the population.

Example: The duration of three periods is set to 5, 2, 7 days; for group 1 the control is set to 0.8, 0.3, 1. This means that you alternate 5 days with a light control (20% contact reduction) with 2 days with a strict control (70% contact reduction), followed by a period of 7 days without any control. If there are several groups, the level of periodic control for each group must be specified.

Note: For technical reasons, it is not possible to enter the same value twice. However, for the periodicity, setting 5, 5.1 or 5.9 will always yield three periods of 5 days. The same is true for the control values, which can be set to 0.881 and 0.88 for instance.

cite: Sofonea MT, Reyné B, Elie B, Djidjou-Demasse R, Selinger C, Michalakis Y, Alizon S (2020, medRxiv)
Epidemiological monitoring and control perspectives: application of a parsimonious modelling framework to the COVID-19 dynamics in France