Is my cloth mask good enough to take on the Delta variant?



In recent months, some European airlines have prohibits the use of fabric face covers to control the spread of the coronavirus during air travel, focusing instead on surgical masks – sometimes called medical or disposable – and N95 respirators.

It’s another salvo in the debate over the effectiveness of the ubiquitous cloth mask, which became fashionable when surgical masks and N95s were harder to come by at the start of the pandemic. Centers for Disease Control and Prevention Still Promoting Fabric Face Coverings in its mask guidelines.

And masks remain a critical mitigation tool because people become infected mainly with SARS-CoV-2, the virus that causes COVID-19, by inhaling small aerosol particles that linger in the air or large respiratory droplets produced during coughing and sneezing.

But science is evolving. Delta, currently the main variant in the United States, is much more contagious than the original coronavirus, so the density of the virus in the air is greater.

Some experts have adjusted their advice proportionately. “Considering the delta variant that exists, you probably need to upgrade your mask” Dr Ashish Jha, a great COVID expert and dean of the Brown University School of Public Health, said the “Fox News Sunday” earlier this month.

What type of mask should you wear?

Don’t worry if you are confused. Advice on masks has been mixed since the dawn of the pandemic, and new research has shifted conventional thinking. We decided to dig in and sort out the latest developments.

First of all, people were told that masking was not necessary. Soon after, this recommendation changed, but the public was advised against purchasing surgical-style masks used by healthcare professionals due to the severe shortage of such protective equipment. Instead, Americans were told to get cloth masks or make do-it-yourself versions. Shortages don’t seem like such a big issue now, although the CDC always advise against choose N95 respirators.

As recently as late August, the country’s top infectious disease doctor, Dr Anthony Fauci, declined to recommend better quality masks. “Instead of worrying about the type of mask, just wear a mask”, he said “The Mehdi Hasan Show” on MSNBC.

So, what gives? Dr Peter Chin Hong, an infectious disease expert at the University of California-San Francisco, said Fauci is taking a harm reduction approach. “It’s probably more important to wear something that you feel comfortable with, and that you can wear for long periods of time if you’re going into a particular environment… rather than saying you have to wear the gold standard. at any time. ” he said.

“A baseline should be a surgical mask,” Chin-Hong added. “It’s easier to implement. It’s cheap, but not always environmentally friendly. Personally, he only wears N95s when forest fires are on fire. “Even in the hospital, I mainly wear a surgical mask,” he said.

Although he believes the government and public health officials should focus on wearing surgical masks, Chin-Hong said cloth masks may provide sufficient protection under certain circumstances. For example, a fully vaccinated person, he said, would likely get adequate protection by wearing a cloth face covering for brief periods indoors when the site is not at full capacity. It depends a lot on the context, so he asked these questions to help the decision-making process: If you go inside, will the building be particularly crowded? How long will you be inside? Will everyone likely be masked? Are you and others around you fully immunized? Are you immunocompromised?

The more risky the situation, the more likely the better quality mask is the better option. “Nothing is zero risk, so it’s just a matter of risk reduction,” Chin-Hong said.

“So definitely the masks need to be beefed up to tackle the delta, but that doesn’t mean those who can’t afford N95s have no options,” said Raina MacIntyre, head of the research program on the delta. biosafety at the University of New South Wales in Sydney, Australia, which has conducted numerous studies on masks.

MacIntyre said it was “possible to design a high performance cloth mask.” An experimental laboratory study that she co-wrote found that a layered fabric mask can effectively block droplets. The study, published in May in the journal ACS Science and Engineering of Biomaterials, recommends using a minimum of three coats – a combination of cotton / linen and polyester / nylon – to resemble the droplet blocking performance of surgical masks.

Not only is layering important for improving filtration, it is too. A technique recommended by the CDC to improve the fit of a surgical tissue or mask tie the suspenders and go inside The sides. A mask is usually a good fit if you feel hot air coming through the front of the mask as you inhale and exhale.

What does the research say?

A large-scale real-world study published this months, surgical masks have been particularly effective in reducing symptomatic infections. These types of masks prevented 1 in 3 infections in people 60 years and older.

Researchers from Yale, Stanford and the nonprofit GreenVoice followed more than 340,000 adults in rural Bangladesh for at least eight weeks. About half of Bangladeshis have benefited from interventions such as the distribution and promotion of free masks. The villages which benefited from interventions saw the use of the mask increase from 13% to 42%. The same villages reported fewer confirmed COVID infections and a lower incidence of associated symptoms.

Villages where cloth masks were distributed reported an 8.5% reduction in symptoms, while villages that received surgical masks reported a 13.6% reduction. When a third of adults with symptoms commonly associated with COVID agreed to have their blood tested for the virus, researchers found an 11% reduction among those who wore surgical masks. Researchers observed a 5% reduction in infections among those who wore fabric masks. This study was conducted before the delta variant circulated widely in the country. The study has not yet been peer reviewed, but some connoisseurs have already announced its methodology and results.

“When I saw these results, I threw away my cloth mask,” said Stephane Luby, study co-author and professor of infectious diseases at Stanford University. “If the delta is going around and you’re going to wear a mask, why don’t you wear one that the data tells you is good?”

“We find very strong evidence that surgical masks are effective,” added Jason abaluck, a Yale economist who helped lead the study. “My reading of this is that cloth masks are probably somewhat effective. They are probably better than nothing.

Abaluck suspects his study offers mixed evidence for sheet masks, as only about a third of those who reported symptoms consented to blood tests for COVID. In other words, the sample size was too small to observe anything significant. “The most likely interpretation of this whole constellation of results is that [cloth masks] really help. In fact, they make you less likely to contract COVID. This is why we have seen fewer symptoms, ”he said. A second possibility is that the cloth masks prevent other respiratory illnesses with similar symptoms, he said.

Multiple observational studies and trend analyzes found that community masking, which includes the use of cloth masks, reduces the spread of COVID. Researchers from the Bangladesh study said there were drawbacks to these studies, which is why they conducted a randomized clinical trial. For example, some of these studies were unable to observe the independent effect of masks in real-life conditions, as they examined the consequences of mask warrants, which were often associated with other COVID mitigation measures such as than physical distancing. However, they agreed with the overall assessment of those studies: People who wear masks are less likely to be infected than people who don’t.

“This is the nature of science. Science evolves, ”said Luby. “We had evidence that we get some protection from cloth masks, and now we have new evidence that we get better protection from surgical masks. “


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