First case of covid-19 reinfection in the US 1:17
(CNN Business) -
(CNN Business) -
Plexiglass barriers are now ubiquitous in offices, supermarkets and restaurants across the US in the era of the coronavirus.
They were even installed on the stage of the vice presidential debate last week.
Since they are almost everywhere, you may wonder how effective they really are.
Businesses and workplaces have noted that Plexiglass dividers are a tool they use to protect people from the spread of the virus.
But it is important to know that there is little data to support its effectiveness.
Even if there are, barriers have their limits, according to epidemiologists and aerosol scientists who study airborne transmission of the virus.
Guidance from CDC
The US Centers for Disease Control and Prevention (CDC) has provided guidelines for workplaces to "install physical barriers, such as clear plastic sneeze guards, when possible," such as a way to "reduce exposure to hazards."
The Department of Labor's Occupational Safety and Health Administration (OSHA) has issued similar guidance.
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That's because Plexiglass shields can theoretically protect workers from the large respiratory droplets that spread if someone sneezes or coughs alongside them, say epidemiologists, environmental engineers and aerosol scientists.
The coronavirus is believed to be transmitted from person to person "primarily through respiratory droplets that are produced when an infected person coughs, sneezes or talks," according to the CDC.
What the experts say about plexiglass
But those benefits have not been proven, according to Wafaa El-Sadr, a professor of epidemiology and medicine at Columbia University.
The professor explained that there have been no studies that have examined how effective Plexiglas barriers are in blocking large droplets.
Plus, the biggest problem is that even if they do, that's not the only way the coronavirus spreads.
Last week, the CDC released new guidelines noting that coronavirus can be spread through aerosols - tiny particles that contain the virus and float in the air and can travel beyond two meters - that are released when the people breathe, talk, or sneeze.
Most of the droplets that people release when they speak or breathe have a "range in size that will pass the barrier," said Pratim Biswas, an aerosol scientist at Washington University in St. Louis.
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The splitters "do not address all possible modes of transmission, such as aerosol transmission, nor do they fully protect anyone from COVID-19," the University of Washington's Department of Environmental Health and Safety said in a July review of the benefits. and limitations of plexiglass barriers in campus facilities.
There is also another problem in some cases: the size of the barriers.
Marissa Baker, an assistant professor at the University of Washington, has been conducting a separate study of coronavirus safety measures at nine grocery stores in Seattle and seven in Portland, Oregon, each month since May.
Limitations of installed plexiglass barriers
Businesses and workplaces say that Plexiglass dividers are a way to keep people safe from the spread of the coronavirus.
She has observed that the Plexiglas shields on cash registers and self checkout stations are often too small to prevent droplet transmission between customers and workers.
"Some are smaller and do not even cover a tall individual's nose," he said.
"Airborne particles are going to be able to get anywhere, regardless of the barriers," he added.
Restaurants and retail industry trade groups say they view barriers as a potential way to combat the spread of COVID-19, in conjunction with other measures.
“We know much more now, and we follow scientific data to guide our decisions.
Based on the recommendations of public health authorities, it would be important to consider layered controls in any setting, ”a spokesperson for FMI, a grocery industry trade group, said in an email.
The use of masks and the maintenance of physical detachment "remain two effective means of mitigating the risk of contracting the virus."
The National Restaurant Association of America said in a statement that Plexiglas shields and barriers are a tool that "when combined with other best practices, such as face covering, appropriate physical distancing, and hand washing, provide a additional level of security '.
However, depending on where you work or where you visit, these measurements can be unrealistic.
For example, cashiers and waiters cannot do their jobs without being close to customers.
This is why improving ventilation systems is important to reduce the spread of the virus in the air indoors, experts say.