Fig. 1
From: Optimizing COVID-19 surveillance in long-term care facilities: a modelling study
Characteristics of the SARS-CoV-2 transmission model. a A diagram of the baseline LTCF, showing the average weekly number of patients and staff in each ward, including “Other” staff not primarily in any one specific ward. Below the LTCF is a description of the epidemiological scenarios considered for how SARS-CoV-2 was introduced into the LTCF. b A snapshot of the simulated dynamic contact network, showing all patients (PA, circles) and staff (PE, triangles) present in the baseline LTCF as nodes, and inter-individual contacts aggregated over one randomly selected day as edges. Nodes and edges are coloured by ward, with grey edges representing contacts across wards. c A diagram of the modified SEIR process used to characterize COVID-19 infection (S, susceptible; E, exposed; IP, infectious pre-symptomatic; IA, infectious asymptomatic; IM, infectious with mild symptoms; IS, infectious with severe symptoms; R, recovered), with transitions between states a to f (see Additional File 1: Table S1). Below, diagnostic sensitivity of RT-PCR for detecting SARS-CoV-2 in a true positive specimen was modelled as a function of time since infection