Wearing Face Masks - theory or reality ?

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Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Study highlights the importance of mask fit when double masking to protect against COVID-19


https://www.news-medical.net/news/20210 ... ID-19.aspx

A study published today in JAMA Internal Medicine shows that wearing two face coverings can nearly double the effectiveness of filtering out SARS-CoV-2-sized particles, preventing them from reaching the wearer's nose and mouth and causing COVID-19. The reason for the enhanced filtration isn't so much adding layers of cloth, but eliminating any gaps or poor-fitting areas of a mask.

" The medical procedure masks are designed to have very good filtration potential based on their material, but the way they fit our faces isn't perfect."

- Emily Sickbert-Bennett, PhD, Associate Professor of Infectious Diseases, UNC School of Medicine and Study's Lead Author

To test the fitted filtration efficiency (FFE) of a range of masks, UNC researchers worked with James Samet, PhD, and colleagues in the USEPA Human Studies Facility on the campus of UNC-Chapel Hill. There they filled a 10-foot by 10-foot stainless-steel exposure chamber with small salt particle aerosols, and had researchers don combinations of masks to test how effective they were at keeping particles out of their breathing space.

Each individual mask or layered mask combination was fitted with a metal sample port, which was attached to tubing in the exposure chamber that measured the concentration of particles entering the breathing space underneath the researcher's mask. A second tube measured the ambient concentration of particles in the chamber. By measuring particle concentration in the breathing space underneath the mask compared to that in the chamber, researchers determined the FFE.

"We also had the researchers in the chamber undergo a series of range-of-motion activities to simulate the typical motions a person may do throughout their day - bending at the waist, talking, and looking left, right, up and down," said Phillip Clapp, PhD, an inhalation toxicologist in the UNC School of Medicine who has been testing mask FFE with Sickbert-Bennett since the pandemic began.

According to their findings, the baseline fitted filtration efficiency (FFE) of a mask differs person to person, due to each person's unique face and mask fit. But generally, a procedure mask without altering the fit, is about 40-60% effective at keeping COVID-19-sized particles out. A cloth mask is about 40% effective.

Their recent findings on doubling of face masks, shows that when a cloth mask is placed over a surgical mask, the FFE improved by about 20%, and improved even more with a snug-fitting, sleeve-type mask, such as a gaiter. When layered over procedure masks, cloth masks improve fit by eliminating gaps and holding the procedure mask closer to the face, consistently covering the nose and mouth. When a procedure mask is worn over a cloth mask, FFE improved by 16%.

"We've found that wearing two loosely fitted masks will not give you the filtration benefit that one, snug-fitting procedure mask will," Sickbert-Bennett said. "And with the current data supporting how effective mask-wearing is at preventing the spread of COVID-19, the best kind of double-masking is when you and the person you are interacting with are each correctly wearing a very snug-fitting mask."

This study was partially funded by a grant from the Centers for Disease Control and Prevention (CDC), and expands upon research conducted by the agency earlier this year, which supported the CDC's recommendation of double-masking to the public. Sickbert-Bennett and Clapp have previously discussed this recommendation and their research on the importance of mask fit with news outlets in a recorded conversation, which can be seen here.


University of North Carolina Health Care
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Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Experts debate on wearing masks outdoors


https://www.news-medical.net/news/20210 ... doors.aspx

Mask wearing by the public, particularly outdoors, remains controversial. But should masks be worn outside, in some circumstances, to help reduce covid-19 virus transmission - or should efforts focus on reducing indoor transmission where risks are greater?

Experts debate the issue in The BMJ today.

Babak Javid at the University of California San Francisco and colleagues acknowledge that the risk of covid-19 virus transmission is far greater indoors than outdoors. Nor do they support policies that mandate masking outdoors when someone is alone or only with members of one household.

But they argue that wearing masks outdoors, particularly at large outdoor gatherings with prolonged close interactions, should be normalized because it may reduce virus transmission and encourage mask wearing indoors, where risks are greater.

They say fears of increased transmission after mass protests in support of the Black Lives Matter movement were not realized, whereas the mass outdoor Sturgis Motorcycle Rally in South Dakota, USA, is thought to have been the trigger for a huge superspreading-type event.

One proposed reason for these differences is that the Sturgis Rally was associated with lower compliance with measures such as mask wearing and physical distancing that are associated with decreased transmission risk, they explain.

They also point to data from the US and Germany showing that regions with public mask mandates have had a lower impact from the virus, while countries with early adoption of face coverings for the public also achieved an earlier acceptance of a social norm during the pandemic.

In summary, they argue that “wearing masks outdoors, particularly at large outdoor gatherings such as sporting events or other settings where it will be difficult to maintain physical distance for prolonged periods, which may have a low but measurable risk of seeding a superspreading event - as well as normalizing mask wearing behavior in general - will bring benefits in reducing risks during the pandemic phase of covid-19.”

But Dr Muge Cevik at the University of St Andrews and colleagues argue that outdoor transmission contributes very little to overall infection rates and efforts should focus on reducing indoor transmission.

No confirmed sizeable covid-19 clusters or “superspreader” events have been outdoors-only, they say. While the Sturgis Rally in South Dakota or the Rose Garden outbreak at the White House are frequently cited as evidence for outdoor-only superspreading events, these events had sustained and multi-day indoor components. For instance, epidemiological investigation of Sturgis Rally found cases linked to restaurants and workplaces.

Given the low risk of transmission outdoors, recommendations or mandates for outdoor masking may seem arbitrary, affecting people’s trust and sustained energy to engage in higher yield interventions, such as indoor mask use or staying home if sick, they write.

What’s more, an outdoor mask requirement “might serve as a disincentive to be outdoors, which could worsen social isolation.”

Equity concerns are also vital, they add, because people who have access to back gardens or can afford private transport to less population dense areas can enjoy the outdoors unmasked, while many others without such privileges or resources cannot enjoy fresh air or exercise unmasked in settings where mask use is universally mandated outdoors.

They believe the public should be informed about the evolving scientific understanding of transmission mechanisms and should be encouraged to be most vigilant in indoor settings, while noting that prolonged and close contact outdoors may pose a risk.

Ultimately, outdoor mask mandates may be popular in some settings, as they are among the most “visible interventions” purporting to demonstrate decisive leadership, they write.

“However, these mandates do little to tackle the real transmission risks or to address outcomes of socioeconomic inequities and structural racism, driving a disproportionate number of the infections and consistent disparities observed worldwide,” they conclude.

A linked article asks what do we know about airborne transmission of SARS-CoV-2? The World Health Organization is currently of the opinion that viral transmission by aerosols, while possible for covid-19, is not the main route by which SARS-CoV-2 spreads.

And in a linked commentary, The BMJ’s patient editor explains why she wears a mask indoors and out.

" Wearing a mask doesn’t mean that you are weak or cowardly. It’s a way to protect vulnerable people around you. I am vaccinated, yet I wear a mask inside or outside in solidarity with those who are still vulnerable.”

- Dr Muge Cevik, University of St Andrews



Journal reference:

Javid, B., et al. (2021) Should masks be worn outdoors?. BMJ. doi.org/10.1136/bmj.n1036.
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Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Editor of BMJ Evidence-Based Medicine calls for end to masks in schools, declares zero evidence they prevent anything


https://pandemic.news/2021-04-29-editor ... dence.html

Professor Carl Heneghan, a professor of evidence-based medicine and editor of the British Medical Journal (BMJ) publication Evidence-Based Medicine, has issued a warning that face masks are “useless” at protecting against infection with the Wuhan coronavirus (Covid-19).

During a recent appearance on British news, Heneghan explained that forcing children to wear a face covering all day long while at school is especially pointless – and many would say harmful – because cloth and plastic have never been proven to stop the spread.

“In the absence of evidence, if you think they should be wearing them, go and talk to some children,” Heneghan says. “That’s what I’ve done and said, ‘What’s the reality on the ground? What’s it like for you in class? How does it feel?’ And I can tell you they hate them.”

“They find it really difficult. They don’t adhere to the guidelines, so, for instance, they go in the pocket to pull them out. That’s a dangerous issue with co-infections and the potential for that to stay infected for a period of time.”

Heneghan believes in taking a common sense, precautionary approach when it comes to imposing interventions like masks that have the potential to cause harm. The government seems to be mandating them willy-nilly using not science but fear and superstition as backing. In Heneghan’s apparent view, this is a mistake.

“So, I think, look, it comes back to at the end of the day common sense. And, in effect, we’re going in two weeks’ time, they’re being told they can remove them,” he says.

“I think, again, the government should start to look cool and calmly at the data, and then think, ‘Where does it have an evidence base and where doesn’t it?’ And that’s all I ever do is say, ‘Where’s the evidence to inform what we do?’ And if it’s lacking, then you have to err on the side of not intervening.”

Heneghan directs the NIHR SPCR Evidence Synthesis Working Group, a collaboration of nine primary care departments across various universities in the United Kingdom. He also directs the Oxford Covid Evidence Services, which oversees more than 400 peer-reviewed publications.

Heneghan further edits the Catalogue of Bias, a consortium of definitions, explanations and examples of some of the most important biases that can affect health research.
If your children are struggling to breathe every day, you have Fauci to thank

That someone of this caliber is speaking out against masks says a lot. As far as we can tell, Heneghan is more in-the-know than Anthony Fauci, who seems to know nothing about public health, hence why he is constantly flip-flopping about the simplest things.

At first, Fauci said masks were bad. Then they were good. Then they were bad again. Now they are good again. The guy just cannot get his story straight, and tens of millions of innocent children are now having to suffer through the school day muzzled and suffocated.

“The sun kills the virus and it is blatantly stupid and child abuse for these kids to be wearing masks,” wrote one commenter at Citizen Free Press.

“There is no evidence masks work,” wrote another. “They don’t stop infections or transmission of viruses, but they do harm health and may lead to death in immunocompromised people.”

Yet another pointed out that while a mask might block large particles like dust while you are sweeping your garage, they certainly are not effective at blocking microscopic virus particles that pass right through their mesh with almost zero resistance.
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