Effectiveness of quarantine measure on transmission dynamics of COVID-19 in Hong Kong

Hsiang-Yu Yuan; Axiu Mao; Guiyuan Han; Hsiangkuo Yuan; Dirk Pfeiffer

Schema of susceptible-exposed-infected-quarantined-recovered meta population model. Imported cases arrive as exposed (E) status before disease onset in order to pass through the border. Imported cases then become infectious (I), quarantined (Q) or recovered (R) statuses. βη 1 Rpt M is the rate to produce imported cases, where η is a function to determine the probability of an ill passenger can pass the border (see Methods for the details). R pt is the reporting ratio in Mainland China and M is the mobility rate. Both imported and local cases are able to infect susceptible individuals (S) and cause local transmission while quarantined cases have a lower transmission rate depending on the recontact ratio (q), indicating the ratio of the contact rates of quanratined to unquarantined individuals. Epidemiological parameters β is the transmission rate, τ is the latent periods, γ is the recovery rate, T qr is the time to quarantine after being infectious. ∆I imp (σ)D represents the newly detected imported cases, where D is the detected ratio defined as the ratio of the number of quarantined imported cases to the total number of infectious and quarantined imported cases, and σ is the pre-symptomatic transmission period, indicating the delayed time of symptom onset after being infectious. Similarly, ∆I loc (σ)D represents the detected local cases.