Are KN95 Masks Reusable? All You Need To Know to Venture Out Safely
Masks. Face coverings. Filtering facepiece respirators (FFRs). Whatever loving moniker you choose to bestow upon them, they have quickly become both a public health and fashion mainstay for the duration of the COVID-19 pandemic, or until Dr. Fauci says it’s okay to put them away. But they are an exercise in futility if not used properly.
KN95: Not a Mask For Your Dog – Though That’d Be Cute!
The U.S. Food and Drug Administration (FDA) defines an N95 mask as “a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of airborne particles.”
What is the difference between KN95 masks and N95 masks? KN95 masks are the Chinese version of the U.S. N95 masks, scored by China’s standards, and both are considered FFRs, which means they are both negative pressure air-purifying particulate respirators in the form of a mask.
Due to the dire situation created by the lack of a U.S. storehouse of masks, or the manufacturing capacity to create the necessary personal protective equipment (PPE) early on in the pandemic, hospitals had turned to China, purchasing KN95s in droves.
However, researchers at the ECRI Institute, America’s largest patient safety organization, issued a hazard warning in September 2020 after analysis showed that up to 70% of K95 masks did not meet U.S. National Institute for Occupational Safety and Health (NIOSH) standards for effectiveness. The nonprofit’s research found that of the nearly 200 imported KN95 masks from 15 different manufacturers, 60-70% did not actually filter 95% of aerosol particulates.
While warning against the use of KN95 masks by healthcare institutions when dealing directly with COVID-19 patients, the institute did promote their value in clinical settings involving limited contact with bodily fluids.
“KN95 masks that don’t meet U.S. regulatory standards still generally provide more respiratory protection than surgical or cloth masks and can be used in certain clinical settings. Hospitals and staff who treat suspected COVID-19 patients should be aware that imported masks may not meet current U.S. regulatory standards despite marketing that says otherwise,” said Michael Argentieri, vice president for technology and safety at ECRI.
A second study, conducted by a team of researchers from Harvard and MIT calling themselves the Greater Boston Pandemic Fabrication Team (PanFab), raised alarm bells about potential counterfeits among the KN95 masks.
“Due to the absence of publicly available information on mask suppliers in the FDA EUA and confusing or inconsistent labeling of KN95 masks, it is difficult to distinguish legitimate and counterfeit products,” said the scientists.
The main concern remains the KN95 mask’s regulation and lack of standardization.
“A KN95 is not usually fit-tested but N95 masks are evaluated, tested, and approved by NIOSH. Therefore, although a KN95 mask may block 95% of viral particles, there is more variability to KN95 masks with N95 masks being standardized,” said Dr. Monica Gandhi, MD, an Infectious Diseases Doctor and Professor of Medicine at UC San Francisco. “However, in general KN95s are well-fitted and made of a nonwoven polypropylene material that should block a large proportion of viral particles.”
Are N95 and KN95 Masks Reusable?
FDA guidance states that all N95 respirators cleared by the agency are labeled as "single-use," disposable devices.
However, when the COVID-19 pandemic exploded, it quickly depleted PPE supply chains across the globe, and medical systems and individuals alike were forced to pivot to plan B, C, and even D. So, when put in this position, it became important to weigh decontamination options.
Changjie Cai, Ph.D., and Evan Floyd, Ph.D., both professors at the University of Oklahoma, conducted a study comparing the filtration efficiency of N95, KN95, and surgical face masks prior to and post sterilization with a hydrogen peroxide and chlorine dioxide solution. The masks began with an effectiveness of 97.3%, 96.7% and 95.1% respectively, and fell to 95.1%, 76.2% and 77.9% after sterilization. Note that KN95s in particular did not stand up against this method of cleaning.
Water was found to be the safest way to clean N95 and KN95 masks as each retained at least 95% of its original efficiency.
The Unsung Benefits of Masks
Gandhi, along with many other fellow scientists, has conducted epidemiological studies showing that masks may reduce the actual viral inoculum – or amount – of the SARS-CoV-2 we contract.
“[Masks] prevents the wearer from getting infected, so there’s a transmission benefit. And then our idea, along with others, because we’re not the only one pushing this viral inoculum idea, is that it will also help us have less severe disease if we do get infected,” Gandhi told BioSpace in a previous interview.
Each vaccine currently approved under an FDA EUA provides robust coverage against severe disease and hospitalization. Even the much-debated AstraZeneca-Oxford vaccine displayed this efficacy in its U.S. phase III trial.
Are Masks Here to Stay?
The question on everyone’s mind. You’ve received at least one COVID-19 inoculation: At one point can you store the mask for Halloween?
“The mask mandate should be lifted once everyone in a state – in the case of the U.S. since mask mandates are generally state-based – who wants a vaccine can get two doses of it,” said Gandhi. “This is because those who are vaccinated are protected from infection and because those who are vaccinated protect the nonvaccinated since these vaccines reduce transmission.”
Gandhi pointed out, however, that masks may now be part of the fabric of North American life, saying:
“There is a difference between a mask mandate, which is a public health measure, and people wanting to wear masks in the future once we can all get vaccinated. It is likely a number of people will opt to wear a mask, especially during respiratory viral season following a pandemic like COVID-19, but a public health mandate will not be indicated.”