iStock Just like many people have a favorite pair of shoes right next to the front door, there’s a good chance you have a go-to mask. Maybe it ends up in your purse, jacket pocket, or the floor of your car, but your trusty mask is there for you for every grocery store run or trip to the mall. So how long exactly can you wear a KN95 mask? If you’ve had your mask for a while, you may be wondering if it’s actually still as effective as it was when you first strapped it over your face. If you’re putting in the effort to protect yourself (and others) you want to make sure your mask is actually working, right? PSA: Your KN95 mask loses its effectiveness over time and there’s a very good chance you’re overdue for a new one. Here’s everything you need to know—and how to make your mask last as long as possible. 

Why KN95 Masks Are So Effective At Protecting Against COVID-19

While infectious disease experts emphasize that any mask is better than no mask, the KN95 mask has become the gold standard in protecting against COVID-19. Dr. William Schaffner, MD, a professor of infectious diseases at the Vanderbilt University School of Medicine, says the major reason for this is simply because KN95 masks fit better than fabric masks. “In the medical field, KN95 masks are called respirators because they are more effective than surgical masks,” he says. Dr. Schaffner explains that when a KN95 mask is fit tightly around the nose, cheeks, and chin, a person breathes almost 100 percent through the material, which is not the case with cotton masks, which leave gaps. Infectious disease specialist Dr. Michael Barry, PhD, says there’s another reason why KN95 masks are so effective at protecting against COVID-19: the material. “The multiple layers [typically a polypropylene plastic polymer] overlap each other to create pores that only a certain size particle can pass through,” he says. In the medical field, KN95 masks are designed for one-time use, but both the experts and the Centers for Disease Control and Prevention say that the average person can use the same mask more than once. The CDC advises people to replace their mask after wearing it five times, based on the results of a scientific study published in the American Journal of Infection Control. However, there are other specific factors that play into how long your KN95 mask can last.

How to Make Your KN95 Mask Last As Long As Possible

Since one of the core reasons why KN95 masks are so effective is because of their tight fit, Dr. Schaffner says that one tell-tale sign that your mask should be thrown out is if it’s losing its shape. “It’s not a good idea to put your KN95 mask in your pocket, purse, or anywhere else it can easily get crumpled,” he says. “I like to keep mine in the glove compartment of my car because there isn’t much in there and my mask is able to maintain its shape,” he says. He also says that properly storing your mask will prevent it from getting covered with debris as quickly. Dr. Schaffner says that another way to make your KN95 mask last longer is to prevent it from getting wet, to the best of your ability. Water destroys the integrity of the mask’s materials and a wet mask should be thrown out. This also means that attempting to sanitize your mask by washing it with soap and water won’t work. In fact, Dr. Schaffner says there isn’t a great way to disinfect a KN95 mask at all, so if it’s dirty he recommends just throwing it out and getting a new one. What about if you’ve worn your mask around someone that you know has COVID-19? Is it still okay to wear your mask a few more times? Dr. Barry says that it’s safest to get a new mask. “Theoretically, COVID-19 has some shelf-life on solid surfaces,” he says, but he adds that it’s hard to truly know how much of a risk it is to continue wearing the same mask after a COVID-19 exposure. The bottom line is that there’s a good chance you’re wearing your KN95 mask a lot longer than is recommended. Again, it bears repeating that any mask is better than no mask. But if you truly want to protect yourself from COVID-19 as best as possible, replace your mask after five wears and be sure to keep it somewhere clean, where it won’t lose its shape. With this advice in mind, you’ll have proper mask-wearing … well, covered. Next up, find out why you shouldn’t be trying to catch Omicron on purpose.

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Dr. William Schaffner, MD, professor of infectious diseases and preventive medicine at the Vanderbilt University School of MedicineDr. Michael Barry, PhD, infectious disease specialist at Mayo Clinic How Long Can You Wear a KN95 Mask  Doctors Explain - 55