Skip to main content
. 2021 Sep 27;532:110919. doi: 10.1016/j.jtbi.2021.110919

Table D.2.

Model variables and parameters.

Variable/Parameter Description Estimation
Variables
S(t),E(t),I(t) (Non-quarantined) susceptible, exposed and infectious individuals
Sq,Eq(t),Iq(t) Self-quarantined (social-distanced) susceptible, exposed and infectious individuals
Sc(t),Ec(t),Ic(t) Contact-traced susceptible, exposed and infectious individuals
R(t) Isolated reported cases
Rc(t) Currently quarantined contact-traced cases
Parameters
β,βq,βc Transmission rate (for unmonitored infectious) 1,2,
ϕ,ϕqϕc Proportion of (non-quarantined,self-quarantined, already initially traced) contacts traced (or remaining traced) 3, ϕq=ϕ,ϕc=1
σ self-quarantine (social distancing or lockdown) factor 3
p probability of transmission upon contact 3
νq,νc Reduction in susceptibility for self-quarantined, contact-traced susceptible individuals 2, 0
αq,αc Rate of exit from self-, contact-traced quarantine 2, 14 (days)
θc Fraction of susceptible individuals who return to “social-distanced” (self-quarantined) after completing contact-traced protocol 1
τ Average time to infectiousness (includes pre-symptomatic) 3 (He et al., 2020)
T,Tq,Tc Average infectious period (time to isolation) of non-quarantined, self-quarantined, contact-traced 4.64, 2.71, 2.71 (Bi et al., 2020)
S(0)=N Total initial susceptible population 4

1. β fitted under various assumptions (see Table D.1, Table D.5 & D.6).

2. Fixed at 0 in simplified model, fit in full model (see Table D.3).

3. Fit in full & simplified model (see Table D.1, Table D.3).

4. Population or aggregated populations of provinces in China (N.B. of Statistics of China, 2019).