Masks

Science & Medicine

Masks

Masks — Not just for the Other Guy.

NYT, Dustin Chambers

Mostly, it’s for the other guy.

That’s what the CDC first told us about the wearing of masks.

So while the rest of the world — particularly in Asia where experience of epidemic viral infection is fresh — wore masks and got control — and in some cases got rid — of COVID-19, maskless Americans saw infection and death rates soar. Soon the United States was the by far the world’s leading pandemic death and infection statistic.

Today Dr. Anthony Fauci, the CDC and the World Health Organization recommend everyone wears a mask in public to help prevent getting infected.

It took 150,000 deaths in the US before several State Governors reluctantly mandated wearing of masks in public areas. And even at that local groups sued against the prospect and the President retweeted videos ridiculing the wearing of masks. So what’s the truth? Do masks help the wearer or do they just protect the other guy from being infected by us?

“Now,” reports the New York Times, “as cases continue to rise across the country, experts are pointing to an array of evidence suggesting that masks also protect the people wearing them, lessening the severity of symptoms, or in some instances, staving off infection entirely.

Different kinds of masks “block virus to a different degree, but they all block the virus from getting in,” said Dr. Monica Gandhi, an infectious disease physician at the University of California, San Francisco. If any virus particles do breach these barriers, she said, the disease might still be milder.

Dr. Gandhi and her colleagues make this argument in a new paper slated to be published in the Journal of General Internal Medicine. Drawing from animal experiments and observations of various events during the pandemic, they contend that people wearing face coverings will take in fewer coronavirus particles, making it easier for their immune systems to bring any interlopers to heel.”

Dr. Gandhi quotes data from cruise ships, “which pack big groups of people into close quarters. More than 80 percent of those infected aboard Japan’s Diamond Princess in February — before masking had become common practice — came down with symptoms, she noted. But on another vessel that left Argentina in March, and on which all passengers were issued surgical masks after someone onboard came down with a fever, the level of symptomatic cases was below 20 percent.”

Safeguarding yourself and others from this deadly disease, she added, “is as simple as covering up the two holes in your face that shed the virus.”

Who benefits from masking?

A Patient Care study published by the University of California. San Francisco focused on the science, how masks work and what to consider when selecting a mask.

“Two compelling case reports,” according to the Study, “suggest that masks can prevent transmission in high-risk scenarios, said Peter Chin-Hong, MD and George Rutherford, MD. In one case, a man flew from China to Toronto and subsequently tested positive for COVID-19. He had a dry cough and wore a mask on the flight, and all 25 people closest to him on the flight tested negative for COVID-19. In another case, in late May, two hair stylists in Missouri had close contact with 140 clients while sick with COVID-19. Everyone wore a mask and none of the clients tested positive.”

“I think there’s enough evidence to say that the best benefit is for people who have COVID-19 to protect them from giving COVID-19 to other people,,” says Dr. Chin-Hong. but you’re still going to get a benefit from wearing a mask if you don’t have COVID-19,” said Chin-Hong.

Masks, contend Chin-Hong, may be more effective as a “source control” because they can prevent larger expelled droplets from evaporating into smaller droplets that can travel farther.

A closer look at the passage of the tiny CORVID-19 virus, less than 1/10 of a nanometer in size and easily able to penetrate the pores of a mask was provided in a recent Scientific Roundtable at the AAAS

“Yes a single virus particle is only about 0.1µ in diameter. However when it is emitted by an individual it is in a much larger droplet partially dictated by surface tension favoring larger particles. That droplet of mucus containing materials does contain about 1% or so of soluble polymer materials whose mass make the virus particle look like nothing. On something like a cloth mask material that is hydrophilic that mixture of water, surfactants, mucus and a little fraction of virus will be adsorbed on the fibers and the water evaporated leaving a virus particle wrapped in polymer fibers not going anywhere.”

What makes a good mask?

According to the WHO, fabric masks should ideally have at least three layers: an inner layer made with absorbent material (e.g., cotton), an outer layer with water-resistant material (e.g., polyester), and a middle layer (made with absorbent or water-resistant material) to act as a filter. In addition, says Raina MacIntrye, professor of biosecurity at the University of New South Wales, , “the design should fit around the edges of the face because air will flow down the path of least resistance.” In other words, if there are gaps on the sides of your mask, your breath will slip through those cracks instead of being filtered through the mask itself.

“The concept is risk reduction rather than absolute prevention,” said Chin-Hong. “You don’t throw up your hands if you think a mask is not 100 percent effective. That’s silly. Nobody’s taking a cholesterol medicine because they’re going to prevent a heart attack 100 percent of the time, but you’re reducing your risk substantially….

“The bottom line.” says Dr. Chin-Hong, ” is that any mask that covers the nose and mouth will be of benefit.”

Note on N95 masks... According to the MAYO CLINIC “Some N95 masks, and even some cloth masks, have one-way valves that make them easier to breathe through. But because the valve releases unfiltered air when the wearer breathes out, this type of mask doesn’t prevent the wearer from spreading the virus. For this reason, some places have banned them.”

Both Rutherford and Chin-Hong also cautioned against N95 masks with valves (commonly used in construction to prevent the inhalation of dust) because they do not protect those around you. These one-way valves close when the wearer breathes in, but open when the wearer breathes out, allowing unfiltered air and droplets to escape. Chin-Hong said that anyone wearing a valved mask would need to wear a surgical or cloth mask over it. “Alternatively, just wear a non-valved mask,” he said.