CHICAGO (NewsNation Now) — Top infectious disease expert Dr. Anthony Fauci is among a number of health experts who’ve recently recommended wearing an extra mask to protect against coronavirus infection.

With the recent emergence of several variants believed to be more transmissible, health officials are emphasizing the importance of effective mask-wearing and social distancing until more of the population gets vaccinated.

British officials have recently warned that the strain first detected in the U.K. — and now confirmed in at least 22 states across America — was associated with a higher level of mortality. Scientists have said existing vaccines still appear effective against it, though some worry about a variant first detected in South Africa. That strain may reduce the efficacy of current vaccines, and shows resistance to three antibody treatments developed for patients.

“The one that’s more troublesome is the one from South Africa,” Fauci said in an interview with WGN Radio Tuesday. “The one in the U.K., which is now in at least 22 states in the United States, it seems to be well protected by the vaccines that we have currently available, namely the Moderna and the Pfizer vaccine. The situation is a little bit more ominous for South Africa because their mutation diminishes somewhat the efficacy of a vaccine but not to the point where it makes it ineffective. So, there’s enough cushion of protection, from the vaccines that are available, that even a diminution of a bit that we know now does occur with the South African mutation, it still does not evade the protection of the vaccine, in other words, the vaccine still works.”

Fauci said that double-masking is “likely better” at protecting from the virus and the new, more contagious, variants.

“This a physical barrier, so you talk about possibly double masking, which, just from common sense, would tell you that if one physical barrier would help you, if you strengthen that with another mask or an underlying cotton mask underneath, it’s likely better than one,” Fauci said. “That’s not a firm recommendation, it just makes common sense.”

Fauci also stressed that despite the vaccine remaining effective against the new strains, viruses tend to continue to evolve, and the best way to ensure the vaccine’s continued efficacy is to reduce the replication of the virus by getting vaccinated.

The benefits of double-masking

Dr. Anne Rimoin, an infectious disease epidemiologist at UCLA’s Fielding School of Public Health, told NewsNation on Monday that there’s a lot of new data emerging about the effectiveness of layering masks.

“If you must wear a thin mask, make sure it’s very well-fitting and wear a second one on top of that,” Rimoin suggested.

“Each cloth mask is about 50% effective, but if you double it up, you end up with about 75% efficacy at preventing spread of this virus,” she explained.

Dr. Monica Gandhi, an infectious disease physician at UCSF, recently worked with a virus transmission expert on a medical commentary on the principles of the importance of face masks, and the data supporting double-masking.

“It is what we just wrote about, surgical masks block the virus electrostatically. It’s almost like electrical pulsion, and then the cloth mask blocks it in the fibers and it can’t get through, and putting those two together are as effective as an N95,” Gandhi told NewsNation affiliate KRON.

Are there better alternatives?

If you can’t double up or don’t want to, some health experts suggest buying higher-quality masks.

“A double mask will offer better protection and if you’d rather not do a double mask, update your mask quality to a K95 or N95,” Dr. James McDonald, medical director of Rhode Island’s Department of Health, told NewsNation affiliate WPRI.

“I doubt you can find medical-grade N95 masks and quite frankly, that’s OK. Leave them for those working in the hospital,” McDonald said.

But he said K95 “are readily available and have been so for months now.”

McDonald also said there are masks that no one should be wearing, even as a second layer.

“As much as I hate to say it, you know the ‘gator’ masks? Those are probably not helpful anymore, and these tube-like masks, we are beyond them,” he said. “I probably wouldn’t use them. They don’t really give you any protection and they are not even the best at source control.”

Reuters and NewsNation affiliates KRON and WPRI contributed to this report.