Each week, we answer "frequently asked questions" about life during the coronavirus crisis. If you have a question you'd like us to consider, email us at goatsandsoda@npr.org with the subject line: "Weekly Coronavirus Questions."

Between face shields, neck gaiters and goggles, the options for protection are getting more complex. What face covering setup offers the best safeguard from the virus?

There's been a lot of face covering news this week. A study from Duke looked at the effectiveness of a variety of coverings and resulted in headlines like this from The Washington Post: " Wearing a neck gaiter may be worse than no mask at all, researchers find."

Lovers of neck gaiters — those tubes of fabric you slip over your head and that pull up over the nostrils and mouth — were up in arms.

Then the Philippines ruled that you have to wear a plastic face shield when going outside.

One thing is clear from the research: Wearing a face covering can save lives.

But there's still a lot we don't know.

The neck gaiter debate illustrates why there's still confusion.

Outdoor exercisers often like gaiters — they're easy to pull up and down, and there are no ear loops that might pinch the ears or simply slip off.

But this week, a study from Duke appeared to conclude that wearing a gaiter is worse than no mask at all when it came to protection. (The researcher hypothesized that the gaiter's porous texture would likely split large COVID-19 particles into many smaller ones, which then can linger in the air for longer.) And the media was quick to jump on the story.

Dr. Michael Edmond, infectious disease specialist at the University of Iowa, has a few points to make about the study.

"One thing to realize is that they [tested only] one gaiter, made of neck fleece — which is a very thin fleece," Edmond says. That's a synthetic material. He says: "I'd be interested to know if the gaiter tested was made of a different fabric with multiple layers if it'd be more protective."

In other words, he'd like to see more data before knowing whether to discount all gaiters.

And that's true in general about face coverings that seek to protect others from any viral particles emitted by the wearer — and protect the mask-wearer as well.

Dr. Vicente Diaz, who specializes in ocular inflammatory and infectious diseases at Yale Medical School, agrees, He says while Duke's study provides a good starting point, there are many other factors to consider in assessing gaiters — like testing circumstances and the specific gaiter used.

"What they found was that when the subjects were talking for ten minutes, [gaiters] seemed to allow particles [spewed by the wearer] to break up and even spread faster," he says. "But that may be a function of the material used, as well as the design of the face covering."

What's more, outdoor exercisers are ... outdoors ... where risks of transmission are lower than indoors. And runners may also be following the guidelines of social distancing, which would further decrease risks to others — which is why some reports have said you shouldn't be so hasty to trash your gaiter.

One ScienceNews story, by Jonathan Lambert, concedes that there is indeed much to be learned still about masks' role in helping prevent the spread of COVID-19. But according to Monica Gandhi, an infectious disease specialist at the University of California, San Francisco, cited in the story, the "preponderance of evidence, both for COVID-19 and earlier viruses, suggests that cloth face masks, and that includes properly worn neck gaiters, filter out the majority of viral particles and provide some protection for an individual."

Then there's the question of full-on plastic face shields.

Edmond thinks they're pretty cool.

When it comes to larger viral droplets, he says, a face shield is likely more protective than a face mask.

Furthermore, a face shield covers the eyes — a potential entry point for the virus — he points out. That's something no gaiter or mask can do.

And while it's easy to wear a mask incorrectly — letting it slip beneath the nostrils or hang from the chin — that's not going to happen with a face shield.

The shields are also easy to clean with spray disinfectant, or just soap and water, says Edmond.

Then again, face shields aren't 100% effective either.

"The downside [with face shields] is that we don't know how well they work for source control," Edmond says — in other words, limiting your transmission of viral particles if you're infected. "That's another thing we're waiting on data to really give us an answer for."

As such, Edmond says the safest approach combines a mask and a face shield to offer maximum protection from viral particles for yourself and for others. He notes that when a face shield is worn over a mask, it can offer the advantage of protecting the mask itself — keeping it from picking up virus particles.

Diaz emphasizes that eyes are another area to protect, if you have the ability to. He says studies have found that when eye protection was incorporated as a part of disease control strategy, it substantially reduced the rate of coronavirus infection.

"When it comes to the eyes, we've learned that they do seem to be involved," Diaz says. "Certainly the virus can get to the eye, and approximately 60% of people who present with COVID infection have been noted to have eye-redness as a presenting symptom."

Edmond says it's probably easier for most people to wear face shields than skin-tight goggles when it comes to eye protection. However, it depends on your preference. If you need to protect your eyes and don't want to wear a shield, goggles would work. Just make sure they are in fact goggles and not safety glasses, which you can tell by their "fairly tight contact to your face" with no gap.

"If fitted appropriately, goggles will be very protective" he says.

Diaz says eye protection can even start from the simplest choices — even just opting for glasses instead of contacts can confer an additional barrier. In the end, the best protection is one you will actually wear — so it's a good idea to do as much as you're comfortable with sticking to consistently.

As a general rule, Diaz says it's critical to consider your own health risk when determining a mask or face covering regimen. If your day-to-day is particularly high-risk — say, you're a healthcare worker — or you're immunocompromised, "the more protection the better."

Edmond says he tailors his personal face gear to the situation.

"If I'm going to the grocery store, where I don't anticipate that there are going to be people very close to me, I will typically wear a shield, unless the store says specifically I have to wear a mask," he says. "But if I have to be in a classroom where there are lots of people per square footage — I would probably wear a mask and a shield. And same thing if I'm on a plane."

Diaz follows a similar setup – wearing a surgical mask in public, and an N-95/face shield combination at work, where he works closely on the eyes of patients. Diaz says the most protective options are masks with respirators that filter out viral particles, or N-95 masks, though for most people, they're hard to access.

But a mask that has an exhalation valve or vent — making it easier to breathe — gets a thumbs down from the Centers for Disease Control and Prevention. In guidance updated late last week, the CDC explains that one-way air vents allow air (and thus, potentially infected respiratory particles) to be released, so valve masks fail to prevent COVID-19 transmission.

"For the general public, we're in consensus that at least a cotton mask is helpful," Diaz says. "Beyond that," he says, "the more you do to protect yourself, "the better."

Pranav Baskar is a freelance journalist and U.S. national born in Mumbai.

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