A new study backs the growing body of evidence that the coronavirus can spread more quickly in enclosed spaces.
In the study, published in the JAMA Internal Medicine, researchers established a link between the community outbreak of the virus in China to a source patient who spread the virus on an air-conditioned bus.
Study lead author Ye Shen from the University of Georgia in the US said in a statement: "Our study provided epidemiologic evidence of transmission over long distances, which was likely airborne."
The study further revealed that close contact through droplets is a major cause of the transmission of the virus.
"However, the widely adopted social distancing and handwashing did not effectively prevent transmission globally. Instead, the number of new Covid-19 cases increased steadily," said Shen.
The research team, with the help of epidemiologists from two regional Centers for Disease Control and Prevention in China, traced infections after the large outdoor worship event in Zhejiang province.
Researchers noticed that some attendees also changed buses while commuting.
Study co-author Changwei Li stated that both buses had closed windows and had ACs, but one had a positive patient, while the other had all the negative patients.
The passengers who were infected with the virus travelled on the same bus as the source patient.
Researchers observed that the transmission rate was much lower at the event as compared to the bus. This suggests that the AC bus carrying the coronavirus patient was the major point of transmission.
These findings stressed the fact that coronavirus can be transmitted through fine aerosol particles that are suspended in an enclosed space.
"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," Shen noted.
"Our findings provide a solid support for wearing face-covering in enclosed environments with poor ventilation," the team wrote.