Contact tracing-induced Allee effect in disease dynamics

Area of Science:

• Epidemiology
• Mathematical Modeling
• Public Health Interventions

Background:

• Non-pharmaceutical interventions (NPIs) like social distancing and case isolation are key to managing pandemics.
• The impact of NPIs on disease dynamics, particularly contact tracing saturation, remains incompletely understood.
• Healthcare systems globally recognize contact tracing saturation as a critical factor.

Purpose of the Study:

• To model the contact tracing saturation process and its effect on disease dynamics.
• To investigate the emergence of an Allee effect due to contact tracing saturation.
• To analyze the interplay between NPIs, vaccination, and disease containment thresholds.

Main Methods:

• Developed both mechanistic and phenomenological models to simulate contact tracing saturation.
• Analyzed the induction of an Allee effect and its role in determining infection thresholds.
• Examined the synergistic effects of combining different containment strategies.

Main Results:

• Contact tracing saturation induces an Allee effect, establishing a critical infection threshold.
• This threshold can lead to two distinct states: containment or outbreak.
• Individual interventions show diminishing returns, while combined strategies enhance suppression.
• The timing of NPI implementation and relaxation is crucial for effectiveness.

Conclusions:

• Contact tracing saturation is a significant factor influencing epidemic tipping points.
• Combined interventions are more effective than individual strategies for disease containment.
• Careful management of NPI relaxation, especially post-vaccination, is vital to prevent resurgences.
• Understanding these dynamics can guide public health strategies for epidemic management.