Japanese study shows face shields do not stop the spread of smaller airborne droplets


Earlier this week there were headlines about the fact that the CDC had removed, then replaced, coronavirus guidelines stating that the virus could be spread through airborne particles that hang in the air, not just droplets transmitted person to person. This would have huge implications on reopening guidelines, however we know that science does not matter to this administration. I heard a scientist on NPR say that in a normal administration, six months into a deadly pandemic, we would be getting daily briefings from the CDC. Of course this isn’t happening because Dear Leader wants to control the narrative. We’re now hearing that morale is of course low at the CDC and that staffers are frustrated by the fact that they’re being undermined by the administration and by senior CDC officials kowtowing to them. We’ve seen Republicans try to deny climate science for years, now that millions of lives are more immediately at stake how is it surprising that they’re not behaving any differently?

In another piece of news that is frustratingly not surprising, a Japanese study found that face shields don’t protect against the spread of coronavirus. Using a simulation with a supercomputer, they found that all smaller droplets escaped from people wearing a face shield. The shield only blocked half of the larger droplets.

Riken, a government-backed researcher center in Kobe, Japan, conducted the study by using Fugaku, the world’s fastest supercomputer, according to the New York Times and the Guardian.

Results from the study reportedly proved that nearly 100 percent of airborne droplets less than 5 micrometers in size escaped through the plastic shields. In addition, about half of larger droplets measuring 50 micrometers found their way into the air, the Guardian reported.

Makoto Tsubokura, a team leader at Riken, strongly recommended that regular face masks be used instead of plastic face shields for protection from the virus.

“Judging from the results of the simulation, unfortunately the effectiveness of face guards in preventing droplets from spreading from an infected person’s mouth is limited compared with masks,” he told the Guardian.

Tsubokura also said that those who have been advised to not wear face masks, such as people with respiratory issues or young children, can use face shields instead — but only outdoors or in properly ventilated indoor areas.

[From People]

I’d be curious to know if these shields actually prevent droplets from reaching the wearer. Like do they work for people wearing them, but not for everyone around them? I would assume they’re ineffective as personal protection too. I live in rural Virginia. The only people I see wearing face shields are workers, like at stores or during food pickup. I try not to go through their lines.

Very few non-workers are wearing shields, but I’d rather see someone with a shield than without a mask entirely. The shields do have eye protection when worn with masks, and may keep people from touching their faces. I think they should be used along with masks, and should not be allowed as alternatives to masks.

Incidentally, the study that supposedly showed that neck gaiters were worse than wearing no mask only tested one kind of gaiter in a very small study. Even the scientists said that the reports about it were inaccurate. It sounds like this study is much more reliable.

Also, face masks are truly effective and are helping not only stop the spread of coronavirus, but may decrease the severity of the virus for mask-wearers who get it. Kaiser pointed me to this Twitter thread (segment below) and article detailing a new opinion piece in the New England Journal of Medicine. Scientists theorize that masks may be “helping to reduce the severity of the virus and ensuring that a greater proportion of new infections are asymptomatic.” This is just a theory so far, based on the idea that exposure to a smaller viral load creates less severe symptoms, but it sounds so promising.

Wearing a mask could reduce the infectious dose that the wearer is exposed to and, subsequently, the impact of the disease.

Population-wide mask-wearing might ensure that a higher proportion of #Covid19 infections are asymptomatic pic.twitter.com/6ynzAWnEnO

— The Telegraph (@Telegraph) September 24, 2020

— Dr. Robert R. Redfield (@CDCDirector) September 22, 2020

photos credit: Ian Panelo via Pexels and Julian Wan via Unsplash

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