How different masks protect against Covid-19, its delta and omicron variants

How different masks protect against Covid-19, its delta and omicron variants
Image: Clarisa Diaz / Quartz
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Masks help prevent the spread of infection, both with the original Covid-19 virus, and the omicron variant that is taking hold of the US, and other variants like the delta variant.

According to the US Centers for Disease Control and Prevention (CDC), the omicron variant will spread more easily than the original Covid-19 virus and can spread to others even if they are vaccinated or don’t show any symptoms. Its mask guidelines recommend that people wear masks indoors while in public. That’s because face masks reduce the transmission of the delta, omicron, and other Covid-19 variants as well as they do for the original Covid-19 virus. Mask wearing by vaccinated people reduces the risk of breakthrough infections.

It’s worth taking a look again at which masks are out there, and the pros and cons of each.

N95 mask protection

An illustration of a N95 mask.

N95 masks or FFP2 masks offer the best protection against the Covid-19 virus, delta and omicron variants. N95 masks filter 95% of particles in the air as small as 0.3 microns. The CDC says healthcare workers and other workers who work in hazardous conditions should have prioritized access to N95 masks. Only buy and use N95 masks if there’s an abundant supply in your area.

KN95 mask protection

An illustration of a KN95 mask.

The next best option against Covid-19 is a KN95 mask or an FFP2 mask, also filtering up to 95% of particles in the air as small as 0.3 microns in size. The difference between N95 and KN95 masks is how they are certified. N95 masks follow a US standard whereas KN95 masks follow a Chinese one. The standards are very similar, but the differences mean that N95 masks usually have headband straps, while KN95 masks have ear loops.

When purchasing KN95 masks, look to see if they meet requirements similar to those set by the National Institute for Occupational Safety and Health (NIOSH).

According to the CDC, these masks are suitable for situations that require prolonged close contact with people who do not live in the same household, or for people who are at increased risk for severe illness.

The downsides to KN95 masks are that they can be uncomfortable, require more effort to breathe, and may not be readily available.

Surgical masks protection

An illustration of a surgical mask.

These masks are commercially available, more comfortable, and affordable. However, surgical masks are harder to fit properly. A poor fit causes gaps around the nose and along the sides of the face where respiratory droplets containing the virus leak in and out. Masks with tie cords and nose wires can help improve fit. The ear loops of surgical masks can also be knotted to fit more snugly. Since the omicron variant is more contagious than the original Covid-19 virus, it’s even more important to make sure masks are properly fitted. Look for surgical masks with multiple layers of non-woven material.

Masks with exhalation valves or vents

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These masks are not recommended by the CDC or the World Health Organization because the valves and vents allow respiratory droplets containing the virus to escape. You could infect the people around you if you have the coronavirus and are wearing a mask with a vent.

Protection from cloth masks and gaters

An illustration of a cloth mask.

The effectiveness of cloth masks depends on how porous the fabric is. Look for cloth masks made of multiple layers of tightly woven, breathable fabric. One way to test a cloth mask is by holding it up to a light source and seeing if the mask blocks the light.

Cloth masks can be made at home and customized for the best fit. They are also more comfortable, affordable, washable, and reusable. But for the omicron variant, a cloth mask alone may not provide enough protection. If possible, experts advise wearing a high-quality three-ply surgical mask, N95 or KN95 mask.

Layering multiple masks for more protection

An illustration of a surgical mask layered underneath a cloth mask.

If high-quality masks are not accessible, then surgical masks can be layered underneath cloth masks for improved fit and filtration. The cloth mask holds the surgical mask in place. Layering masks may be less comfortable and less breathable than a single mask alone, but is more effective at controlling the spread of delta and omicron variants than either of the masks alone.