Assessing the effectiveness of test-trace-isolate interventions using a multi-layered temporal network

Area of Science:

• Epidemiology
• Public Health
• Network Science

Background:

• Non-pharmaceutical interventions (NPIs) are critical in early infectious disease outbreaks.
• Test-Trace-Isolate (TTI) is a key NPI, reliant on effective contact identification.

Purpose of the Study:

• To model transmission dynamics using a multi-layer temporal contact network.
• To assess the impact of various TTI strategies on outbreak containment and epidemic mitigation.
• To use SARS-CoV-2 as a case study for evaluating TTI effectiveness.

Main Methods:

• Development of a multi-layer temporal contact network model.
• Simulation of different Test-Trace-Isolate (TTI) implementation scenarios.
• Evaluation of TTI effectiveness based on outbreak containment and epidemic burden reduction.

Main Results:

• TTI with home isolation and testing of primary/secondary contacts contains outbreaks up to a reproduction number (R) of 1.3 (88.2% prevention potential).
• For R > 1.7, TTI mitigates disease burden but incurs high social costs (e.g., >1 month isolation/quarantine).
• Contact quarantine strategies show higher epidemic prevention potential than those avoiding contact tracing or requiring pre-isolation testing.

Conclusions:

• Relying solely on TTI for novel pathogens like SARS-CoV-2 presents challenges for outbreak containment.
• TTI effectiveness is sensitive to contact pattern modeling; comprehensive social interaction data is vital for preparedness.
• Combining TTI with other social distancing measures can enhance outbreak control but has limitations at high R values.