The current pandemic has placed available PPE supplies at an all-time low. Many front-line providers are forced to reuse face masks that would have normally been thrown away. The result is lots of anxious providers, myself included, worried about spreading infection to ourselves, our patients, and those around us. Fortunately, studies have shown that pathogen transfer remains low from breathing through a used mask. Research shows that the greatest risk in reusing N95s is that we cross-contaminate ourselves or those around us with germs that are on the outside of the mask. Are you surprised? I was. So what can we do?
In laboratory studies on N95s, one study found that germs applied to N95 mask material remained infectious for 6 days after application. Another study found that 10% of applied germs survived 4 days on N95 samples, with all samples having detectable levels of the germ on the 10th day after application.
The take-away is those masks we are reusing are fomites (materials which are likely to carry infection) and they put us, the wearer, as well as those around us, at risk of cross-contamination and spreading infection.
During this coronavirus pandemic, what can we do to reduce the risk?
Wearing the mask all day is safer than taking it on and off. (If only they weren't so miserable to wear!) The risk of pathogen transfer from N95s is high by contact (taking it on and off) and low is we just leave it on.
Not taking the mask on and off decreases the frequency of touching the outside of the mask, which is likely contaminated. Being careful to wash hands before and after applying and removing a N95 will reduce the risk of cross-contamination. Storing the mask so it isn't contaminating surfaces or people is important too. But some of us are being asked to store these masks in paper bags and plastic containers, and wearing them day after day. As you read above, those germs aren't going anywhere soon. So how do we keep the masks as germ free as possible?
Keep your N95 covered. NIOSH 'recommends for consideration' wearing a cleanable face shield over the mask as a preferred method to reduce surface contamination of the N95 (like the airmen in the photo are wearing). OSHA also suggests that a faceshield be 'considered' to reduce N95 contamination. The CDC and NIOSH both 'suggest' covering N95s with surgical masks that are changed after each patient encounter, but one study found that a mask worn over a N95 increased work of breathing, which is not what we need when working through a 12 hour shift. Personally, I like the shields, because they protect the whole face and don't fog up like goggles do. Plus, it reminds me to keep my hands away from my face. And if it's good enough for the United States Air Force, it's good enough for me!
Here's the data that is behind the above information. Please take a look. It's very interesting!
ECRI (Emergency Care Research Institute) recently published this report:
Until we have enough supplies to return to disposing of used N95 masks after each use, we need to do everything we can to protect ourselves, our patients and those around us from cross-contamination.
Stay safe out there!