Why dust masks might not be enough as Omicron spreads

Doctors and health systems say it may be time to change your face masks.

With infections increasing due to the rapidly spreading Omicron variant, including among the vaccinated, doctors are now urging people to abandon dust masks, which they say may not provide enough protection against the virus. Instead, they recommend pairing dust masks with surgical models or moving on to stronger respirator masks.

The Mayo Clinic began Thursday requiring all patients and visitors to wear surgical masks such as N95 or KN95 masks. Anyone who wears a single-layer, homemade dust mask, gaiter or bandana, or a mask with a vent, will receive a medical-grade mask to wear over it.

Single-layer cloth masks, which many people prefer for comfort and style, can block larger droplets that carry the virus, but are not as effective at blocking smaller aerosols as particles that carry the virus, according to infectious disease specialists .

Disconnect a KN95 mask

Because KN95 masks have a filter layer made of polypropylene, which is a type of plastic, they are effective at trapping small particles. The extra layer provides a higher level of protection against Covid-19 compared to cloth or surgical masks.

Filter layer:

Made of a type of plastic and where electrostatic filtration occurs

Filter layer:

Made of a type of plastic and where electrostatic filtration occurs

Filter layer:

Made of a type of plastic and where electrostatic filtration occurs

The most recent guidance from the Centers for Disease Control and Prevention advises that people wear masks, including fabrics that are multilayered and tightly woven, that fit well and have an adjustable wire nose bridge. It also suggests laying masks, using a disposable mask under a dust mask and reserving N95 masks for health workers.

But many professionals in the field say that certain masks are more effective than others in protecting people against the Omicron variant and that dust masks alone are not.

“If you really do not want exposure, you need to wear the right type of mask,” says Monica Gandhi, an infectious disease specialist at the University of California, San Francisco. Dr Gandhi recommends N95 masks, which are certified in the US, as the KN95, KF94 and FFP2 masks, which are certified in China, South Korea and Europe respectively. If these are not available, she recommends double masking – a multilayer cloth mask directly on top of a surgical mask. Surgical masks are made of polypropylene, which has electrostatic charge properties that block the virus.

“If everyone just wears a dust mask or just a surgical mask, it will make no difference” with this highly transferable variant, she says.

Well-fitted, certified N95 masks can filter up to 95% of particles in the air.


Photo:

Getty Images

Others in the field say that high-quality, well-worn surgical masks provide protection, but they also want more data and research on how they stand up against Omicron.

N95 masks, which are certified by the US National Institute of Occupational Safety and Health, have a denser network of fibers than surgical or dust masks. That tighter mesh, along with an electrostatic charge in the material, makes such masks generally more efficient at capturing larger droplets and aerosols exhaled by the wearer. They also better block the inhalation of such particles.

Well-fitted, certified N95 masks can filter up to 95% of particles in the air.

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“Every mask is better than no mask. But dust masks and then surgical masks are not as good as N95 caliber masks,” says Ranu Dhillon, a physician at Brigham and Women’s Hospital.

Megan Srinivas, a clinician and infectious disease specialist at the University of North Carolina at Chapel Hill, says she and other family members wear KN95 masks, which have five layers of overlapping material and a tighter fit to reduce drips. escape or entrance. She would recommend the same masks, which come in baby sizes, to parents who are getting ready to send their kids to school in the new year. If these are not available, she suggests disposing of authorized surgical masks.

“We need to educate the public and say that masks of different quality offer different protection,” she says.

Time it takes to deliver an infectious dose of Covid-19

Person who is not infected carries

It will take 25 hours for an infected dose of Covid-19 to transfer between people wearing non-fit N95 respirators. If they use tightly closed N95s – where only 1% of particles enter the face – they will have 2,500 hours of protection.

Person infected is wearing

Person who is not infected carries

Person infected is wearing

It will take 25 hours for an infected dose of Covid-19 to transfer between people wearing non-fit N95 respirators. If they use tightly closed N95s – where only 1% of particles enter the face – they will have 2,500 hours of protection.

Person who is not infected carries

Person infected is wearing

It will take 25 hours for an infected dose of Covid-19 to transfer between people wearing non-fit N95 respirators. If they use tightly closed N95s – where only 1% of particles enter the face – they will have 2,500 hours of protection.

Person who is not infected carries

Person infected is wearing

It will take 25 hours for an infected dose of Covid-19 to transfer between people wearing non-fit N95 respirators. If they use tightly closed N95s – where only 1% of particles enter the face – they will have 2,500 hours of protection.

Graham Snyder, medical director of infection prevention and hospital epidemiology at the University of Pittsburgh Medical Center, says that any quality mask that provides an effective seal and is worn properly – the nose and mouth covered – provides protection.

Dr Synder says he would like data from the CDC on how Omicron spreads and whether the transmission is related to the types of masks. He worries about the number of people in the community who do not wear masks of any kind.

“Mask works. Period,” he says.

Write to Clare Ansberry at clare.ansberry@wsj.com and Nidhi Subbaraman at Nidhi.Subbaraman@wsj.com

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