NEW YORK, NY (CBS Newspath) – For nearly two years, we have been hearing how important it is to mask up to prevent COVID-19 from spreading. But with the new highly contagious Omicron variant, experts say cloth masks do not cut it anymore and it’s time to upgrade.

“The typical cloth mask might be 50% effective and that was OK before. It doesn’t seem to be enough with Omicron,” says Dr. Linsey Marr, a professor of civil and environmental engineering at Virginia Tech. “We have special masks called respirators, such as an N95 that offer much greater protection. They’re able to block 95% of particles that are either going out of your mouth or that you’re breathing in,” she says.

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Dr. Marr studies how viruses move in the air. She says other respirators are also widely available. “Things like a KN95, which is a Chinese version of the U.S. N95, it has ear loop straps and it’s made out of a special material that’s very efficient at filtering out particles. It also is designed to fit closely to your face. There’s a South Korean version called a KF94 that some people call the boat-shaped respirator,” Dr. Marr says.

Three-ply surgical masks can also help prevent contact with infected droplets. “There are ways to really improve the performance of a surgical mask by improving its fit. One way is to use some little kind of clips or toggles on the ear loops so that you can tighten it up so it pulls closer to your face,” Dr. Marr says.

The fit is critical for all masks to ensure the strongest possible protection. “What you need is to have a good seal, especially around your nose, and you want to make sure there aren’t gaps at the sides of your cheeks or at your chin,” Dr. Marr says.

As for kids, Dr. Marr says also choose a good mask that’s comfortable, with good fit and filtration. Some respirators are designed for kids, but N95’s are not designed for younger children.

It’s important to check that a regulating body in the U.S., Chinese governments, or Korean government has approved what you’re purchasing. Counterfeit KN95 respirators are pretty prevalent, and the CDC maintains a list of brands selling counterfeit masks.