How effective is your mask? Here’s what we know now

Amid a slow vaccine rollout and growing reports of a highly contagious new variant of the COVID-19 virus, masks are increasingly being recognized as an essential tool in slowing the pandemic.

But how do you choose? A year after the start of the pandemic, there are still no filtration standards or labeling requirements. Masks range from hospital grade N95s to silky Mickey Mouse gaiters. They may not be suitable. They can filter poorly.

“It really is the Wild West,” said Joseph Allen, associate professor and director of the Healthy Buildings program at the TH Chan School of Public Health at Harvard University.

“We are a year into this pandemic. It shouldn’t take hours and hours for a consumer to try to figure out what a decent mask is, ”he said.

And while there has been great innovation in the areas of vaccines, therapeutics and testing, “it is shocking that we have not seen any innovation from this simple and most effective tool.

But a growing body of research is telling us more about masks. Here are the answers to some of the most frequently asked questions.

Q: What is a good mask?

A: The N95 mask – 95% effective – is the gold standard, but it is rare.

The KF94 mask, the Korean version of an N95 mask, offers high level protection. These masks are rigorously examined.

KN95 masks are the Chinese equivalent of N95. But you need to do your homework to make sure it’s a mask that’s been checked and checked. Buy it only if the manufacturer has a “NIOSH certificate” – which comes from the National Institute for Occupational Safety and Health.

Blue surgical masks are about 70% effective.

A fabric mask can be between 20% and 70% effective, depending on its construction and the fabric used.

– Joseph Allen of the TH Chan School of Public Health at Harvard University.

Q: What about “double-masking”?

A: The Centers for Disease Control and Prevention has not addressed overlay masks.

You might consider layering your face covers if you spend time indoors in crowded spaces or in areas with high transmission rates. Medically vulnerable people could also consider doubling down.

There are two approaches. The first is to wear a tightly fitting, multi-layered fabric covering a surgical mask. The other is to wear a three-layer mask with outer layers of tightly woven fabric.

– Dr Monica Gandhi, Professor of Medicine and Infectious Disease Specialist at the University of California, San Francisco

Q: Which mask is best if I’m just hiking or sitting on a park bench?

A: Choose your mask according to the level of risk for this activity. If you’re jogging without anyone or taking a walk outside with a friend, a simple two- or three-layered fabric mask works well.

If you are conversing, the power to mask doubles if both people are wearing them. This is because the particles have to pass through the material twice – once after being emitted and again before someone inspires them. Research shows that two masks that are 70% effective combine to reduce more than 90% of particles. Two N95s result in an exposure reduction of over 99%.

– Joseph Allen

Q: How to test the fit of a mask?

A: The mask should go over the bridge of your nose, down around your chin and flush with your cheeks.

Every time you put on a mask, perform a “User Seal Check”. Place your hands on the mask to block the air passing through it and breathe out slowly. You shouldn’t feel the air coming out the side or towards your eyes. Then test to make sure it stays in place by moving your head side to side and all around. Try reading aloud and see if it slips when you speak.

– Joseph Allen

Q: Why can’t healthcare professionals reuse N95 masks?

A: In medical settings, a significant percentage of N95 has failed a fit test after four or five “threads” and “withdrawals”. They no longer completely sealed the face.

There are no universal best practice guidelines for the disinfection and reuse of N95. Some research supports sterilizing N95 with bleach. The use of ozone has also been approved by the FDA for certain reusable medical devices. But these tactics require additional research to ensure safety.

– Get Us PPE, a national organization founded by emergency physicians in response to urgent PPE shortages.

Q: I keep my mask stowed in my car. Are you OK?

A: Yes, but if you have a sheet mask you want to wash it daily. Hang it up after you are done using it, as the virus breaks down or becomes disabled over time. How long does it take? It’s influenced by the temperature and humidity of where it’s stored – but over a day you’ll be fine.

– Joseph Allen

Q: Are neck warmers safe?

A: Gaiters are popular because they are often made of a lightweight, breathable material and do not require earrings; they sit conveniently on your neck, like a scarf.

A single-layer gaiter alone is not enough. But when doubled, it is very effective at blocking a range of particle sizes. In experiments conducted by Professor Linsey Marr of Virginia Tech, a lined gaiter blocked over 90% of the particle sizes tested.

– Linsey Marr, professor of civil and environmental engineering at Virginia Polytechnic Institute and State University

Q: How do I clean my mask?

A: Reusable masks should be washed regularly. Always remove masks properly and wash your hands after handling or touching a used mask.

Include your mask with your usual linen. Use regular laundry detergent and the appropriate hottest water setting for the cloth used to make the mask. To dry, use the highest heat setting and leave in the dryer until completely dry.

– CDC

Q: If I am vaccinated, do I still have to wear a mask?

A: Yes. Although Moderna and Pfizer / BioNTech mRNA vaccines are over 94% effective in controlling symptomatic COVID-19, asymptomatic infection could not be ruled out in either of the two trials in vaccinees.

In addition, the duration of vaccine protection is not yet known and widespread vaccination to achieve immunity at the population level – 60% to 70% – will take some time.

– Monica Gandhi

Q: How could the masks be improved?

A: So right now we have masks that have sufficient filtration – 95% or 94% filtration efficiency is great.

But we need masks that fit better, especially in the bridge around the cheek. There have been efforts to develop “add-ons” that you would wear on a mask to help improve fit, but more innovation is needed.