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COVID cluster from Chinese bus trip offers more evidence of airborne transmission – CBS News

A person on a poorly ventilated Chinese bus infected nearly two dozen other passengers with coronavirus even though many weren’t sitting close by, according to research published on Tuesday that offers fresh evidence the disease can spread in the air.

Health authorities had initially discounted the possibility that simply breathing could send infectious micro-droplets into the air, but did a U-turn as experts piled on pressure and evidence mounted.

The article published Tuesday in JAMA Internal Medicine probes the threat of airborne infection by taking a close look at passengers who made a 50-minute trip to a Buddhist event in the eastern Chinese city of Ningbo aboard two buses in January before face masks became routine against the virus.

Researchers believe a passenger, whose gender was not identified, was likely patient zero because the person had been in contact with people from Wuhan, the city where the contagion emerged late last year.

The scientists managed to map out where the other passengers sat, and also test them for the virus, with 23 of 68 passengers subsequently confirmed as infected on the same bus.

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A chart included in a study published September 1, 2020 in the American Medical Association’s monthly JAMA Internal Medicine shows where people sat on a bus in Eastern China during a trip on which a single passenger is believed to have infected 23 others with the new coronavirus. 

JAMA Internal Medicine


What is notable is that the sickness infected people in the front and back of the bus, outside the perimeter of three to six feet that authorities and experts say infectious droplets can travel.

On top of that, the sick passenger was not yet showing symptoms of the disease, such as a cough, when the group made their trip to a religious event.

Researchers also noted the air conditioning simply recirculated the air inside the bus, which likely contributed to spreading of the virus.

“The investigations suggest that, in closed environments with air recirculation, SARS-CoV-2 is a highly transmissible pathogen,” they wrote, referring to the name of the virus.

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An illustration included in an article on the spread of aerosolized coronavirus particles in enclosed spaces in the Environment International journal in September 2020 shows various means recommended to dilute the concentration of virus-laden microparticles in the air, emphasizing fresh air intake. 

Environment International/Science Direct


“Our finding of potential airborne transmission has important public health significance.”

Their study, which includes a diagram showing where each infected passenger sat, adds to the evidence of airborne transmission, including research into how the virus spread between diners’ tables at a restaurant in the southern Chinese city of Guangzhou.

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Cluster Coronavirus

Coronavirus Cluster Linked To California Birthday Party: Officials – HuffPost

A large birthday party held in California amid the state’s stay-at-home order has led to several people testing positive for the new coronavirus, health officials said Saturday.

A person who was not wearing a face covering at the Pasadena event had been coughing among attending family and friends who were also not wearing face coverings or practicing social distancing, the Pasadena Public Health Department said in a statement.

“One person showed up to the party exhibiting symptoms and joking she may have the virus,” Lisa Derderian, a city spokeswoman, told the Los Angeles Times. “The aftermath affected several others who became seriously ill because of one person’s negligent and selfish behavior.”

Lab tests have confirmed more than five cases of COVID-19, the disease caused by the virus, linked to the party. There are “many more ill individuals” as a result, the health department said.

“This is an example of how good contact tracing can identify disease clusters and tell us more about the spread of disease in our community,” said Dr. Matthew Feaster, an epidemiologist with the department.

California has been gradually lifting its Safer at Home Order, issued back in March, though gatherings of people who do not live in the same household are still prohibited. Those who are aged 65 years or older and have underlying medical conditions are also urged not to participate in public recreation or retail curbside pickup.

“The virus remains highly contagious,” said Dr. Ying-Ying Goh, director and health officer of PPHD. “Social distancing, frequent hand washing, and wearing face coverings remain our best defenses against the further spread of COVID-19 in our community.” 

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