As the highly contagious Omicron coronavirus variant continues to spread, some experts say it's past time to reconsider your face mask options -- especially if you're still wearing the cloth variety.

"Cloth masks are little more than facial decorations. There's no place for them in light of Omicron," said CNN Medical Analyst Dr Leana Wen, an emergency physician and visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health, on CNN Newsroom Tuesday.

"This is what scientists and public health officials have been saying for months, many months, in fact," Wen added in a separate phone interview.

"We need to be wearing at least a three-ply surgical mask," she said, which is also known as a disposable mask and can be found at most drugstores and some grocery and retail stores. "You can wear a cloth mask on top of that, but do not just wear a cloth mask alone."

Ideally, in crowded places, "you should be wearing a KN95 or N95 mask," which can be as inexpensive as a few dollars each, Wen added. By having a better fit and certain materials -- such as polypropylene fibers -- acting as both mechanical and electrostatic barriers, these masks better prevent tiny particles from getting into your nose or mouth and must be fitted to your face to function properly.

Changing guidance

During the first several months of the pandemic, health experts discouraged the general public from buying N95 masks, since medical professionals were facing a shortage of personal protection equipment. But it has "been many months since supply of N95s (has been) an issue," Wen said.

Yet the US Centers for Disease Control and Prevention's most recent guidance on selecting, properly wearing, cleaning and storing face masks recommended people avoid N95 masks and instead choose masks with two or more layers of washable, breathable fabric -- which Wen called "a major mistake."

"If we're going to go as far as to say that masks are required -- when we don't come from a mask-wearing culture and people don't like wearing masks -- at least recommend that they wear the most effective mask," Wen said.

Other countries, including Germany and Austria, have "switched their standard to say that a face covering in public must be at least a medical-grade surgical mask" in certain settings, she added.

CNN reached out to the CDC about its recommendations regarding N95s and cloth masks and is still awaiting comment.

Another factor driving change in mask recommendations is a better understanding of Covid-19 and how it spreads, said Erin Bromage, an associate professor of biology at the University of Massachusetts Dartmouth. "It's taken longer for people to appreciate the nature of airborne infection -- that this isn't necessarily a hybrid infection, say with influenza, where it can both be spread by droplets, inhaled a little bit, on surfaces and infect that way," he said. "It appears ... the primary driver of (coronavirus) infection is shared air."

Cloth masks -- encouraged earlier in the pandemic -- can filter large droplets, while more effective masks, such as N95s, can filter both large droplets and the smaller aerosols or particles potentially laden with airborne virus if infected people are present, Bromage said. A cloth face covering also has 75% inward and outward leakage, which the American Conference of Governmental Industrial Hygienists defines as the "percentage of particles entering the facepiece" and the "percentage of particles exhaled by a source exiting the facepiece," respectively.

Properly fitted N95 respirators that are approved by the US National Institute for Occupational Safety & Health can filter up to 95% of particles in the air, according to the CDC. Surgical or disposable masks are around 5% to 10% less effective than N95 respirators, Bromage said, depending on their ASTM International categorization -- with types 1, 2 and 3 ranking just surgical masks from least to most effective.

Why the Omicron variant has been so successful at quickly infecting many people is "unknown at the moment," but it only underscores the role quality masks can play, Bromage said.

"If it is less virus needed, or if it is a person who's infected is putting more virus out, then the role of a mask in this is if we can cut down the amount that you're actually breathing in, you get more time," he added. "If you needed 1,000 viral particles to infect you and you're wearing something that cuts 50% of things down, it's now going to take twice as long to get to that 1,000. If you're wearing one that is a 90% efficient, it's going to take at least 10 times as long before you get infected when you're around somebody (who is infected)."

"We need to be promoting better high-quality masks everywhere, because right now a single-layer cloth mask just isn't cutting it against Omicron," said former US Surgeon General Dr. Jerome Adams Thursday on CNN's AC360. "We need more testing. We need better masking. That's how we get through this."

Swapping out your cloth masks

The National Institute for Occupational Health & Safety has a list of approved N95 respirators, which can be found at some home improvement stores, retailers and drugstores. These masks should have a cup, flat fold or duck bill shape; two straps that go around your head; an adjustable wire nose bridge; and appropriate markings indicating NIOSH approval, the CDC says.

The agency also has resources for determining whether an N95 respirator is counterfeit, and for properly putting it on, taking it off and performing a respirator seal check.

The difference between N95 and KN95 respirators is where the mask is certified, according to Oklahoma's state health department. The US certifies N95s, while China approves KN95s. About 60% of KN95 respirators in the US are counterfeit and don't meet NIOSH requirements, the CDC says. The CDC has a list of signs a KN95 respirator hasn't been approved by NIOSH.

"If they're made to the standard and certified by the appropriate boards in their country like NIOSH here, they all do basically the same thing," Bromage said. "But there is a ton of knockoffs that are not certified in the KN95 side of things, that may meet the standards but they're not certified to meet it. And there's others that clearly don't."

These experts' recommendation to wear better masks isn't a suggestion to trash your cloth masks or go "maskless" when you don't have a medical-grade mask available.

In studies of various face masks, cloth masks with multiple layers and higher thread counts "have demonstrated superior performance compared to single layers of cloth with lower thread counts," but are still less effective than medical-grade masks, according to the CDC. Wearing a cloth mask over a medical procedure mask, as Wen suggested, can better protect you and others by improving fit and therefore filtration capacity, the CDC says.

"If all you have is a cloth mask, it's still better than nothing," Wen said. "But you are not well-protected, and you should know that you're not well-protected. And so if you're going to a crowded indoor setting and all you have is a cloth mask, don't go."

If you're unable to buy medical-grade masks for whatever reason, go to locations that are requiring masks and providing them for free -- such as some train stations, grocery stores or businesses -- and ask for a surgical mask, Wen suggested.