A susceptible individual (S) can become infected, given a time-dependent infection probability λ( t ). This probability depends on the transmission potential of the virus and the social contact behaviour, which due to contact reduction policies is time-dependent. When infected, the individual becomes exposed ( E ). Once exposed ( E ), an individual goes through an incubation time of ε days, after which the individual becomes infectious prior to symptom development ( I p ). A pre-symptomatic infected individual ( I p ) will either become asymptomatic ( I a ), symptomatic with symptoms ( I s ), after a period of ρ days. When asymptomatic ( I a ) the individual will remain infectious for ζ days after which he/she recovers ( R ). When severely symptomatic, the individual will be hospitalized with an age-dependent probability ϕ ( a ) or recover without the need for hospitalisation.