(1) proba > ContactWithInfected (nbPersons)

(2) proba > InfectedToDeath (t, age)

(3) proba > InfectedToSevere (t, age)

(4) proba > InfectedToHealed (t, age)

(5) proba > SevereToDied (t, age)

(6) proba > SevereToHealed (t, age)

(7) t > immunityTimeAfterHealed

(8) proba > SevereToSusceptible (t, age)