The current guidance for safe social distancing may not be enough to stop the spread of COVID-19, a new analysis suggests.
In the report, researchers from the Massachusetts Institute of Technology and the University of Oxford say that other factors, such as ventilation, crowd size, exposure time and whether face masks are worn, should also be considered.
Since the beginning of the pandemic, the advice has been to keep at least 6 meters away from other people inside and outside. “COVID-19 spreads especially among people who are in long contact (within about 6 feet) for an extended period of time,” according to the Centers for Disease Control and Prevention.
However, in the report, published Tuesday in The BMJ, the researchers wrote that “physical distance should be seen as just one part of a broader approach to public health to contain the covid-19 pandemic.”
Lydia Bourouiba, a professor of civil and environmental engineering at MIT and co-author of the report, said, “It’s not just 6 feet and then everything else can be ignored or just masked and everything else can be ignored or just ventilated and everything else can be ignored. “
It is important to distinguish between high-risk and low-risk exposure, Bourouiba said.
Some evidence suggests that the coronavirus can travel more than 6 meters through activities such as coughing and crying, the researchers wrote. In situations with the highest risk, such as indoors with poor ventilation, large crowds, longer contact time and no face coverings, distance should be more than 6 meters. Locations that fall into this category include bars, stadiums or restaurants. In low-risk scenarios, such as in open-air spaces with a few people nearby, less stringent social distance should be adequate.
The researchers developed a color-coded map to show how transmission occurs, based on different types of exposure.
“This is a way to synthesize and, in some sense, translate complex concepts into what we hope is an accessible color-coded map,” Bourouiba said.
Dr. Ezekiel Emanuel, a bioethicist, agreed that the public needs a better sense of risk level from various activities. Emanuel, who was not involved in the new study, said the risk of coronavirus infection comes from four factors:
- inside or outside
- many large
- exposure time
- whether heavy breathing, such as shouting or singing, is involved
“If you’re out there, not in a crowd and for a long time will not be with other people, that’s probably good,” said Emanuel, an oncologist who is vice-provost for global initiatives at the University of Pennsylvania. “Is it a zero-risk scenario? Nothing is zero-risk. Is it a low-risk scenario? Yes.”
Evidence suggests that the 6-foot distance should be at least indoors, said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech.
“People have put too much weight on 6 feet as this dividing line between risky and safe. And this clearly shows that we knew that 6 feet is a guideline, but that the farther the better,” Marr said.
Marr, who is researching how the virus can be spread by aerosol transport, said that contrary to guidelines, everyone should wear masks when they are indoors, even if they are 6 meters from others.
“I’ve seen a lot of guidelines that say you wear a mask when you can’t keep your distance, but I think we should always wear a mask when we’re indoors with other people outside our own homes,” she said.
Exposure time is also very important, because just going through a store with both mask protectors is a low-risk exposure, Marr said.
Eleanor Murray, an epidemiologist at Boston University School of Public Health, said the new data could be useful to public health officials.
“This is just a nice summary of some of the nuances that everyone working in the field of outbreaks is aware of, but has problems conveying to the people who have to make the decision,” he said. Murray.
And Murray and other epidemiologists believe that when students return to classes, school officials should think outside of the 6-foot guidance.
“If they sit in that room – even if they sit 8 meters apart – when they sit together for four hours or two hours together, that increases their risk, even though they do not necessarily have very close physical contact,” he said. se.
This story was originally published on NBC News.
