A Testing and Quarantine Algorithm for Individual International Travelers Using Published Data on WHO-Approved...

Area of Science:

• Epidemiology
• Public Health Policy
• Infectious Disease Modeling

Background:

• COVID-19 pandemic necessitated widespread travel restrictions, including border closures and quarantines.
• Evolving global vaccination rates require adaptive policy modifications for international travel.
• Risk assessment for individual travelers is crucial for balancing public health and mobility.

Purpose of the Study:

• To calculate individual traveler transmission risks based on testing protocols.
• To benchmark these risks against traditional 14-day quarantine without testing.
• To evaluate the impact of test performance and disease incidence on travel policy.

Main Methods:

• Mathematical modeling of traveler transmission risk.
• Benchmarking against unvaccinated individuals in a 14-day quarantine.
• Sensitivity analysis incorporating varying incidence rates and effective reproduction numbers (Rt).
• Evaluation of preboarding and arrival testing strategies with specific sensitivity and specificity thresholds.

Main Results:

• Negative preboarding and arrival tests (sensitivity ≥ 90%, specificity ≥ 97%) are effective for low incidence (≤ 0.1) and Rt (≤ 4).
• High-performance tests (sensitivity ≥ 98%, specificity ≥ 97%) mitigate risk even in high incidence (0.4) and Rt (16) scenarios.
• Fully vaccinated travelers with negative preboarding tests can often be cleared with rapid antigen arrival tests, enabling swift airport departure.

Conclusions:

• Optimized testing protocols can significantly reduce traveler-associated transmission risks.
• Policy adjustments incorporating sensitive and specific testing can replace lengthy quarantines.
• Rapid antigen tests demonstrate potential for facilitating safe and efficient international travel.