Comparative analysis of transmission risk of SARS-CoV-2, influenza and SARS-CoV-1 in a bus environment

Abstract

Background

The Coronavirus disease 2019 (COVID-19) pandemic has posed a substantial threat to global public health. The crowded, poorly ventilated and inadequately air-circulated nature of bus environments may facilitate the rapid transmission of SARS-CoV-2, resulting in clustered outbreak events.

Methods

A quantitative model utilizing a Markov chain approach was constructed to evaluate the transmission risk of respiratory viruses within buses. We compared the infection risk associated with the ancestral strain of SARS-CoV-2, the Omicron variant, Influenza A H1N1 and SARS-CoV-1.

Results

Our findings indicate that the primary transmission route for the ancestral strain of SARS-CoV-2 in buses is via aerosols, while contact transmission plays a negligible role. This pattern is similarly observed with the Omicron variant, Influenza A H1N1, and SARS-CoV-1. Additionally, the Omicron variant of SARS-CoV-2 presents a higher risk compared to the ancestral strain. Both Influenza A H1N1 and SARS-CoV-1 exhibit a higher overall infection risk than either the ancestral or Omicron strains of SARS-CoV-2. Furthermore, the use of masks and increasing the airborne inactivation rate of SARS-CoV-2 are effective in reducing the risk of infection among susceptible individuals in buses.

Conclusions

The study highlights aerosol transmission as the dominant mode of SARS-CoV-2 and other respiratory viruses' spread in bus environments, emphasizing the need for enhanced air disinfection and proper mask usage as key preventive measures. It also notes that modifying surface-related transmission factors has minimal impact on reducing infection risk.