Cost-effective proactive testing strategies during COVID-19 mass vaccination: A modelling study

Area of Science:

• Epidemiology
• Public Health Modeling
• Infectious Disease Control

Background:

• The COVID-19 pandemic imposes substantial human and economic burdens globally.
• Mass testing and isolation of positive cases can mitigate risks, with strategies adaptable to local conditions for cost-effectiveness.

Purpose of the Study:

• To determine the optimal frequency of proactive SARS-CoV-2 testing based on local transmission rates and immunization levels.
• To model the cost-effectiveness of different testing and isolation strategies.

Main Methods:

• A multi-scale model integrating population-level transmission and individual viral load kinetics was employed.
• The model assessed testing frequency, isolation duration, and their impact under varying epidemiological scenarios.

Main Results:

• In high transmission (Re ~ 2.5), daily testing is optimal until 33% immunization, then weekly until 50%, with 10-day isolation.
• In low transmission (Re ~ 1.2), weekly testing is optimal until 10% immunity, then monthly until 20%, with no further testing.
• Cost-effectiveness was evaluated using a willingness-to-pay threshold of $100,000 per year of life lost and a test cost of $10.

Conclusions:

• Proactive mass testing and isolation represent a cost-effective approach to mitigate the COVID-19 pandemic.
• This strategy is particularly relevant during the early phases of vaccination campaigns and when facing vaccine-evasive variants.