Evidence is growing for the airborne transmission of coronavirus disease 2019 (COVID-19) in enclosed spaces, according to a recent study published in JAMA Internal Medicine.

The COVID-19 pandemic has caused more than 1 million deaths and there has been over 33.5 million cases worldwide, according to the World Health Organization. It is largely believed that COVID-19 is spread by close contact through droplets. However, investigators said that widely adopted social distancing measures and increased hand washing failed to prevent transmission on a global scale.

Investigators traced infections to a large outdoor worship event in Zhejiang province, China. Some attendees took 2 buses to the event, both of which had their windows closed and air condition running. One of the buses contained a COVID-19 patient and the other did not.

Of the passengers who got sick, the majority rode on the same bus as the source patient, according to the study. Even after the 2 groups mixed later with the larger crowd, the cases attributed directly to the event were much lower, which suggests that the bus was a major source of transmission, according to the study.

"Understanding the transmission routes of COVID-19 is critical to contain the pandemic, so that effective prevention strategies can be developed targeting all potential transmission routes," lead study author Ye Shen, PhD, associate professor of epidemiology and biostatistics at University of Georgia’s College of Public Health, said in a press release. "Our findings provide solid support for wearing face covering in enclosed environments with poor ventilation."

Reference
Study supports airborne spread of COVID-19 indoors [News Release] September 29, 2020; Athens, GA. https://www.eurekalert.org/pub_releases/2020-09/uog-ssa092920.php. Accessed September 30, 2020.