How Effective Are KF94 Masks in Protecting Against COVID-19 Infection?

If you can't get your hands on an N95 mask, your second best bet is a KF94.

Of all the face masks, N95 is king. But in a worldwide pandemic, these masks can be hard to come by. At the start of the pandemic in March 2020, N95 masks were prioritized for healthcare workers. N95 masks can be purchased in-store or online. Unfortunately, some people have taken advantage of people's desperation to be safe and are selling fake N95 masks. So, plenty of people have turned to KN95 masks, the Chinese equivalent of N95s. Unfortunately, growing scams selling counterfeit KN95 masks make it difficult to know if you are getting a quality mask.

That's why a growing number of people are using KF94 masks, the Korean version of an N95 mask. These masks, which are slightly different from N95s and KN95s, still offer high-level protection, making them a popular option for protection against COVID-19.

Aaron Collins, a mechanical engineer in Minnesota and self-described "citizen engineer" has been testing the filtration properties of KF94 masks and talking up the benefits of these masks on YouTube. Collins told Health he doesn't have any financial ties to KF94 makers and isn't looking to become a social media star—he just wants to inform the public about the best masks out there.

Several doctors and engineers cite Collin's work as the reason people are learning about KF94s. "I've been testing them and screening them, and talking about them from the top of my lungs," said Collins. Collins mentioned he particularly likes the rigorous screening process for KF94 masks. "In South Korea, if you put a KF94 stamp on your masks and don't meet the standards, the government will fine you heavily," explained Collins. "I like these masks because of the quality system in place."

Collins is not the only one giving KF94 masks the thumbs up—plenty of doctors do, too. Here's what you need to know about these masks.

OK, What Are KF94 Masks, Exactly?

The "KF" stands for "Korean Filter," Sara Andrabi, MD, assistant professor of emergency medicine at Baylor College of Medicine, told Health. "The '94' represents the filtration efficiency, which means how well the mask is at filtering out particles. In this case, that is 94%."

"These are basically N95 masks, just from South Korea," infectious disease expert Amesh A. Adalja, MD, assistant professor-adjunct at the Johns Hopkins Bloomberg School of Public Health, told Health.

Like N95 masks, KF94s have an adjustable bridge that works to give you a secure fit over the bridge of your nose. They also have side flaps to contour your face. "These [flaps] help close the gaps around the face and limit unfiltered air entry," said Dr. Andrabi.

KF94 masks are disposable and readily used in South Korea. "It is worn by the general public to help with filtering pollution and dust," explained Dr. Andrabi.

And, along with N95s and (legitimate) KN95s, "these masks are the best types of masks to protect against COVID-19," Thomas Russo, MD, professor and chief of infectious disease at the University at Buffalo in New York, told Health.

How Does a KF94 Mask Compare to an N95 Mask or a KN95 Mask?

An N95 mask (aka an N95 respirator) is a respiratory protective device designed to achieve a close facial fit and "very efficient filtration of airborne particles," according to the Food and Drug Administration (FDA). These masks filter out at least 95% of airborne particles, per the CDC. Similarly, KN95 masks are the Chinese equivalent to N95 masks.

KF94 masks are similar but offer 94% filtration. "There is not much difference between 94 and 95% filtration," said Dr. Andrabi. But, she points out, that the fit is "an important factor" in how efficient these masks are as well. It's also important to note that as of March 2022, KF94 masks are not on the FDA's list for emergency use authorized face masks.

The shape of KF94 masks is different from N95 masks, too. Collins described it as having a "boat-style design," with a wide band that wraps around the center of the mask. N95 masks, on the other hand, have either a cup or duckbill style. "The KF94 mask hits a much wider distribution of faces due to its shape," said Collins.

What Do Doctors Think of KF94 Masks?

Experts said they're worth trying. "Clearly, we need good masks now," Rajeev Fernando, MD, an infectious disease physician working in field hospitals across the country, told Health. "N95 is the gold standard, followed closely by the KN95 and KF94."

But Dr. Adalja pointed out that KF94 masks—along with N95s and KN95s—can be harder to breathe in than cloth face masks. "They're more difficult to wear," said Dr. Adalja, adding, "I don't think that the general public needs to wear a mask at this filtration level." Still, a KF94 "doesn't take away from hospital supplies," which is important for the medical community.

In general, Dr. Andrabi said that "wearing masks helps slow the spread of COVID-19" and the KF94 mask is "another type of mask that is available to the public." KF94 masks aren't perfect, though. "They don't last as long as a cloth mask and cannot be washed," noted Dr. Andrabi. But, Dr. Andrabi added that "wearing the mask you feel comfortable keeping on is of utmost importance."

Where To Buy KF94 Masks

There are some KF94 masks for sale on Amazon, but Collins was concerned about potential counterfeits, given that this has been a problem for the site with other mask styles. "Amazon doesn't have any method of qualifying the vendor," pointed out Collins. "But if you go to Target, Walmart, Lowe's, Ace Hardware, or a store like that, there was someone affiliated with the company who purchased those."

Bizarrely enough, Collins said his tests have found the highest quality KF94 masks through Korean beauty websites like BeHealthyUSA.net. "These sites are the first to import these masks in the US," explained Collins.

Pro tip, per Collins, if you decide to try out KF94 masks: Do a small order and make sure the masks fit your face before ordering more. "If you find out they don't fit, you're going to be left with 99 other masks that don't work for you," advised Collins.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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