Epidemic Network — Contact Tracing & Isolation

SEIQR model on heterogeneous contact networks with intervention strategies

Parameters

Compartments

S Susceptible-
E Exposed-
I Infectious-
Q Quarantine-
R Recovered-
R₀ (eff)-

Theory

SEIQR on network
Effective R_eff = β·⟨k²⟩/(γ·⟨k⟩)
With tracing: R_eff → R_eff·(1-p)
Contact tracing identifies and isolates exposed contacts before they become infectious, reducing the effective reproduction number. Network heterogeneity (hubs) accelerates spread but also offers targeted intervention.