Close contact behavior-based COVID-19 transmission and interventions in a subway system

Area of Science:

• Epidemiology
• Public Health
• Transportation Safety

Background:

• Assessing virus transmission in public transport is crucial for controlling infectious diseases like COVID-19.
• Understanding close contact behaviors of passengers provides insights into disease spread dynamics.

Purpose of the Study:

• To analyze virus exposure and intervention effectiveness in subways using real passenger close contact data.
• To develop and apply a virus transmission model for quantifying exposure risks.

Main Methods:

• Developed a monitoring device to collect 145,821 close contact instances in subways using semi-supervised learning.
• Established a virus transmission model incorporating short-range/long-range inhalation and deposition.
• Analyzed passenger proximity, contact patterns (face-to-back), and interpersonal distances (average 0.8m).

Main Results:

• During rush hour, short-range inhalation exposure was significantly higher (3.2x deposition, 7.5x long-range inhalation).
• Close contact rate was 56.1%, with face-to-back being the predominant pattern.
• Significant exposure reductions achieved by directional seating (74.1% inhalation, 98.5% deposition), reduced talking (69.3% inhalation, 73.8% deposition), and mask usage (82.0% reduction).

Conclusions:

• Passenger behavior and mask-wearing are critical factors in mitigating virus transmission on subways.
• Implementing strategies like directional seating and reducing talking can substantially decrease virus exposure.
• Findings offer scientific evidence for effective COVID-19 prevention and control measures in public transportation systems.