Comparative Analysis of Flight Volume Effects on COVID-19 and Influenza Transmission Across Variable Control Intensities, 2019-2024.

BACKGROUND

Air travel has played a critical role in the global spread of infectious diseases, facilitating rapid movement of pathogens across continents. This study quantifies the effects of intercontinental flight volumes on both influenza and COVID-19 transmission patterns across countries with varying intensities of public health interventions.

METHODS

We analyzed monthly global passenger numbers from January 2019 to July 2024, coupled with comprehensive surveillance data on both pathogens. Using a hierarchical Bayesian linear mixture modeling framework, we examined the relationship between flight volumes and disease activity while accounting for heterogeneity in public health and social measures.

RESULTS

Our analysis reveals that increased flight volumes were significantly associated with both influenza activity and COVID-19 case and mortality rates, with Asian flight spreading rate demonstrating the strongest association with influenza transmission and COVID-19 case rates. These effects were consistently stronger for COVID-19 than influenza and more pronounced in countries with less stringent control measures.

CONCLUSIONS

The comparative approach provides unique insights into how different respiratory pathogens respond to aviation-mediated exposures, demonstrating that targeted travel restrictions can effectively impede disease transmission when implemented alongside appropriate public health interventions. These findings have important implications for the development of pathogen-specific strategies for mitigating the international spread of emerging respiratory threats.