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

Illustrations of masks.
Clarisa Diaz / Quartz
  • Clarisa Diaz
By Clarisa Diaz

Things Reporter

Published Last updated on

Masks help prevent the spread of infection, both with the original Covid-19 virus, and the delta variant that is taking hold of the US, and other variants like the lambda variant and those that will inevitably arise.

While mask mandates were lifted in some locations of the country months ago, the US Centers for Disease Control and Prevention (CDC) recently reversed its masking recommendations even for the vaccinated. Its mask guidelines now recommend that people in areas with high transmission wear masks indoors while in public. That’s because face masks reduce the transmission of the delta, lambda, 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.

So now that there are new mask guidelines again, it’s worth taking a look again at which masks are out there, and the pros and cons of each.

N95 mask protection

N95 masks offer the best protection against the Covid-19 virus and its delta variant. 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

The next best option against Covid-19 is a KN95 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

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 delta variant is more contagious than other variants, it’s even more important to make sure masks are properly fitted.

Masks with exhalation valves or vents

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

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.

Layering multiple masks for more protection

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 the delta variant than either of the masks alone.

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