Understanding small-scale COVID-19 transmission dynamics with the Granger causality test

Area of Science:

• Epidemiology
• Public Health
• Urban Mobility Studies

Background:

• The coronavirus disease (COVID-19) pandemic significantly altered global mobility patterns.
• Understanding small-scale transmission dynamics is crucial for effective public health interventions.

Purpose of the Study:

• To investigate COVID-19 transmission dynamics in Valencia, Spain.
• To assess the role of subway stations and healthcare facilities in disease spread.
• To analyze the temporal evolution of the pandemic at a small-area level.

Main Methods:

• Analysis of 2,398 adult patients' data over the first six months of the pandemic.
• Application of Voronoi segmentation based on subway station and healthcare facility locations.
• Utilizing the Granger causality test to identify transmission patterns within defined city areas.

Main Results:

• Identified 'donor stations' (subway stations with net outgoing connections) primarily at interchange hubs.
• Observed heterogeneous transmission patterns within primary healthcare facilities.
• Highlighted the significant role of interchange subway stations in receiving cases from diverse city regions.

Conclusions:

• Subway interchange stations act as key nodes for COVID-19 transmission due to high connectivity.
• Targeted isolation measures at these high-risk transit areas could effectively mitigate virus spread.
• Public health strategies should consider urban mobility infrastructure in pandemic control efforts.