Exposed people infect others in ABM

[jubicker]

Motivation / Current Behaviour

In the ABM exposed people are infective and are able to infect others.

Enhancement description

Should exposed infect others?

Additional context

No response

Checklist

• Attached labels, especially loc:: or model:: labels.
• Linked to project

[mknaranja]

I just discussed with @DavidKerkmann and here are some thoughts:

• As discussed last week, the parameters SusceptibleToExposedByInfectedNoSymptoms and SusceptibleToExposedByInfectedSymptoms are leftovers of the former transmission modeling were exposed could not infect others. So these parameters should be removed first.
• Now, the ViralLoad is a continuous variable from transmission on and theoretically exposed people can infect others. If this probability is very low, this is probably more realistic than modeling in ODE where the probability to transmit is exactly zero for days. Here, we could mabybe tackle this issue by defining a threshold value for the transmission based on the viral load. If the viral load increases very slowly at the beginning this could be a) realistic and b) in accordance to other models (e.g. ODEs)
• We have a strong inconsistency at the moment: The Exposed state (and others) does not mean anything/much as the corresponding parameter is not coupled/dependent to the viral load or the ability to infect. This should be corrected soon.

There are also some issues that @xsaschako could take over, to make our model reusable in a meaningful way quickly.

[mknaranja]

I forgot:

• The viral_load and infectivity function should be documented in more detail. It should minimally be noted that the viral load is in log scale and it should be mentioned more directly how the exponential function comes into play.

[xsaschako]

Thank you, @mknaranja, @DavidKerkmann . Please take a brief look at the action items here. I will propose code soon, as this will probably be tiny.

• Document viral_load and infectivity function in more detail.
• Delete the parameters SusceptibleToExposedByInfectedNoSymptoms and SusceptibleToExposedByInfectedSymptoms and any leftovers from the previous transition model.

The next one is open to discussion, but maybe a coupling of being exposed with the viral load

• How do we couple infectivity level and status?