In late January, as the brand new coronavirus was starting to unfold from China’s Hubei Province, a group of lay Buddhists traveled by bus to a temple ceremony within the metropolis of Ningbo — lots of of miles from Wuhan, middle of the epidemic.
It was a sunny day with a light breeze, and the morning service was held al fresco, adopted by a transient luncheon indoors.
A passenger on one of many buses had just lately dined with pals from Hubei. She apparently didn’t know she carried the coronavirus. Inside days, 24 fellow passengers on her bus have been additionally discovered to be contaminated.
It didn’t matter how far a passenger sat from the contaminated particular person on the bus, in keeping with a research printed in JAMA Inner Drugs on Tuesday. Even passengers within the final row of the bus, seven rows behind the contaminated girl, caught the virus.
The one issue that will have mitigated the chance of an infection was sitting close to a window that may very well be opened, or close to the door.
The incident provides to a giant physique of proof indicating that the coronavirus may be transmitted by tiny particles that linger within the air, and never simply by way of giant respiratory droplets that fall shortly to the bottom.
The World Well being Group acknowledged the virus may be airborne in July and that these particles may seed superspreader events in closed spaces like restaurants and workplaces.
The new study “adds strong epidemiological evidence that the virus is transmitted through the air, because if it were not, we would only see cases close to the index patient — but we see it spread throughout the bus,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech and a leading expert on airborne viruses.
The two buses carrying passengers to the event had cooling units that were recirculating air inside the vehicles. “That would facilitate the virus in the air and spread it around the bus,” Dr. Marr said. None of the 60 passengers on the second bus was infected.
Dr. Muge Cevik, an expert on infectious diseases and virology at the University of St. Andrews School of Medicine in Scotland, said that the outbreak was likely caused by a combination of factors: a long trip, a confined environment, a crowded bus and an individual who was probably extremely contagious because she was in the early stages of the infection.
“There isn’t really a dichotomy between aerosol and droplet transmission,” Dr. Cevik said. “There have to be multiple things happening at the same time for this type of high risk transmission to occur. This was the wrong place, the wrong time, the wrong person.”
The study’s authors, who are physicians with the Chinese Center for Disease Control and Prevention, concluded that “future efforts at prevention and control should consider the potential for airborne spread of Covid-19.” The study was published previously online as a preprint.
The outing to the Buddhist temple was what scientists refer to as a natural experiment. It took place on Jan. 19, when there were still no confirmed Covid-19 cases reported in Ningbo. The circumstances conveniently allowed for a comparison between similar passengers on two different buses.
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated September 1, 2021
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Why is it safer to spend time together outside?
- Outdoor gatherings lower risk because wind disperses viral droplets, and sunlight can kill some of the virus. Open spaces prevent the virus from building up in concentrated amounts and being inhaled, which can happen when infected people exhale in a confined space for long stretches of time, said Dr. Julian W. Tang, a virologist at the University of Leicester.
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What are the symptoms of coronavirus?
- In the beginning, the coronavirus seemed like it was primarily a respiratory illness — many patients had fever and chills, were weak and tired, and coughed a lot, though some people don’t show many symptoms at all. Those who seemed sickest had pneumonia or acute respiratory distress syndrome and received supplemental oxygen. By now, doctors have identified many more symptoms and syndromes. In April, the C.D.C. added to the list of early signs sore throat, fever, chills and muscle aches. Gastrointestinal upset, such as diarrhea and nausea, has also been observed. Another telltale sign of infection may be a sudden, profound diminution of one’s sense of smell and taste. Teenagers and young adults in some cases have developed painful red and purple lesions on their fingers and toes — nicknamed “Covid toe” — but few other serious symptoms.
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Why does standing six feet away from others help?
- The coronavirus spreads primarily through droplets from your mouth and nose, especially when you cough or sneeze. The C.D.C., one of the organizations using that measure, bases its recommendation of six feet on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet. But six feet has never been a magic number that guarantees complete protection. Sneezes, for instance, can launch droplets a lot farther than six feet, according to a recent study. It is a rule of thumb: Try to be most secure standing six toes aside exterior, particularly when it is windy. However maintain a masks on always, even whenever you assume you’re far sufficient aside.
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I’ve antibodies. Am I now immune?
- As of proper now, that appears possible, for at the very least a number of months. There have been scary accounts of individuals struggling what appears to be a second bout of Covid-19. However specialists say these sufferers might have a drawn-out course of an infection, with the virus taking a gradual toll weeks to months after preliminary publicity. Individuals contaminated with the coronavirus usually produce immune molecules referred to as antibodies, that are protecting proteins made in response to an an infection. These antibodies might final within the physique only two to three months, which can appear worrisome, however that’s completely regular after an acute an infection subsides, stated Dr. Michael Mina, an immunologist at Harvard College. It could be doable to get the coronavirus once more, however it’s extremely unlikely that it will be doable in a brief window of time from preliminary an infection or make folks sicker the second time.
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What are my rights if I’m nervous about going again to work?
Some 300 folks attended the temple ceremony, however solely 128 made the 50-minute journey by bus. One bus carried 68 passengers, together with the person who was contaminated, whereas the second bus carried 60 folks. Not one of the worshipers wore masks.
The paper in JAMA Inner Drugs doesn’t describe the contaminated particular person and says the particular person didn’t have signs till the after getting back from the temple. However a model of the research printed in China says the person was a 64-year-old girl and that she developed signs on Jan. 18, a day after eating with company from Hubei and a day earlier than going to the temple. She took medication however didn’t see a physician.
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“The Chinese language paper says the index case was unwell the day earlier than going to the temple, so she was in all probability very infectious, as a result of we all know that viral load is actually excessive across the time of symptom onset,” Dr. Cevik stated.
The outside ceremony lasted two and a half hours and was adopted by a transient lunch, which occurred in a spacious room that didn’t have recirculating air-conditioning. When the passengers returned to their buses, they took the identical seats that they had occupied earlier.
Along with the passengers who grew to become contaminated, one other seven people who attended the ceremony have been contaminated. They didn’t journey by bus, however stated that they had been in shut contact with the contaminated passenger.
The potential for airborne transmission in shut confined areas raises concern in regards to the winter months, when folks will likely be spending extra time indoors, Dr. Marr stated.
Her recommendation: “Keep away from crowded indoor areas the place individuals are not sporting masks and the air flow is poor.”
