N95 Decontamination Process Allows 25 Reusages


Christina Yen, MD: “For any infection preventionists who are thinking about or are reviewing the need for VHP sometime in the future, just know that those colleagues that we’ve relied on this time around are going to be there and are going to be your partners in the VHP process.”

Imagine technology that could decontaminate N95 respirators for up to 25 times? Christina Yen, MD, an infectious disease specialist at Beth Israel Deaconess Medical Center didn’t need to imagine the technology, just a new way to put it to use. “This isn’t new technology,” Yen tells Infection Control Today®. “But it’s not really been studied in N95 respirators.” Yen’s talking about vaporous hydrogen peroxide or VHP, which hospitals have been using for years to decontaminate various areas. How would the process work with N95 respirators? Great, as Yen demonstrated in a presentation today at the annual conference for the Society for Healthcare Epidemiology of America (SHEA). VHP can decontaminate an N95 up to 25 times. Yen and her co-authors found that “in fact, it was safe, and it did not compromise the way the respirator fits or the way it feels to the face. It works the way it should.”

Infection Control Today®: What did your study entail and what did you find out?

Christina Yen, MD: Sure, of course. Our study at the BIDMC in Boston, Massachusetts, tried to answer the question of how many times can we safely reprocess N95 respirators using a technology called vaporous hydrogen peroxide or VHP. It sounds very scary. But VHP is actually something that hospitals have been using for decades now to clean things like ambulances and rooms. This isn’t new technology. But it’s not really been studied in N95 respirators. We wanted

Christina Yen, MD

Christina Yen, MD

to see if by reprocessing these respirators using this technology, we would be able to retain the fit of the respirator on your face, the way it sealed and the way it worked. And so that’s what we were hoping to find as we reprocess the N95s up to 25 times and we found that, in fact, it was safe, and it did not compromise the way the respirator fits or the way it feels to the face. It works the way it should.

ICT®: Were you surprised by the findings?

Yen: It does seem to buck tradition or convention. And I think that for a lot of us, especially myself, when I first took on this project, I was not sure what we were going to find. But I think what was pleasant to discover was that there actually was a body of evidence that was slowly being built, even before the pandemic, trying to answer this question. Actually, there was a study that was conducted by the FDA [Food and Drug Administration] in 2016, looking at exactly this technology—N95 respirators—to see how many times they could be processed in a safe manner. And so, although it was one study, I think in light of the fact that it was of interest, and because more programs outside of our own program were also doing it, we were developing a body of literature as the months went on during the initial pandemic that was demonstrating over and over that this was, I think, actually not only safe, but probably doable for many of us. I learned a lot in the process, and I read a lot, too.

ICT®: Do you think this sort of decontamination will become part of infection control protocols or will we go back to the old standards?

Yen: I think so long as our supply is able to meet demand, we will likely return to the older or the original standards. And I think that is still reasonable. We do want to ensure that we have an adequate supply of N95 respirators going forward for all of our health care workers. But as you mentioned, I think it is worth noting and retaining this information that we’ve learned because this won’t be the last pandemic and there will certainly be more outbreaks in the future. We in infection control notice. Realizing that we have taken something we’ve learned, something from this experience—as awful as it has been—that will protect health care workers and the patients they care for going in the future. It does need to be retained and we should be able to use this technology and use these strategies when we need to again, when the time comes. There is plenty of hydrogen peroxide to go around. Generally, how it works is that there is actually a machine that is generating or actually converting liquid hydrogen peroxide, which I think a lot of us are familiar with. We have it at home to get out stains or you see it sometimes in the hospitals. It actually converts the hydrogen peroxide from liquid to a gas. And in a contained room where the machine is located and where your respirators are located, that gas actually penetrates the surface of the N95 respirators further in. That actually disrupts the cells and the other viruses and other bacteria, things you don’t want in your respirators. It breaks up the cell walls and deactivates bone. And the best part is—and I think this is something that makes VHP very attractive to many of us—is that once it does its job, hydrogen peroxide breaks up into water and oxygen. All you have to do is ensure that your room is well-ventilated and you blow out your oxygen and water vapor. You really don’t have any dangerous visual things or chemicals on your respirators when they’re done. So long as it’s properly ventilated.

ICT®: What would a decontamination room look like? Would the masks be laid out on tables side by side? I imagine that you wouldn’t want to stack them.

Yen: Correct. You definitely don’t want to stack them. You want to make sure that every respirator is getting its own space so that the hydrogen peroxide gas can settle and get into the respirator. As you mentioned, it depends on the location. Every institution did it a little bit differently. Many folks who did do it liked to opt for shelfs. What you can imagine is there is a room with either shelfs, or some people like lines to hang respirators on. That way each respirator gets space and has enough area for the VHP to circulate. And so, depending on how much space you have in your room, and how much room you have on your shelves or your lines, you can fill it up with many respirators.

ICT®: Do we have enough N95 respirators on hand so we don’t need to do VHP decontamination right now?

Yen: At this time, at least at my institution, we are no longer requiring or needing it because our supplies now are adequate. We’re able to supply folks with respirators, be they N95 or others as people need. I think, ultimately—and I can’t speak for other institutions or the states—but I think many institutions have not necessarily decided to continue using it because supplies have become more available. And I think for that reason, many institutions, such as ours, have considered or are thinking about at this time stopping VHP usage for now. But as you’ve mentioned, and as we’ve talked about, who knows when the next surge will come, the next pandemic will come with the next outbreak. So potentially, in the future, there will be a time and place again.

ICT®: Which department of the hospital would actually do this?

Yen: That’s a great question. And I think the takeaway lesson for me, at least, and I think also for our community, was that it is a team effort. And I think it is reflected in the background of the authors and the contributors for our study. It was not just infection preventionists. It was environmental safety It was health care epidemiologists. So many people from so many different backgrounds with so many different skillsets made this possible. I think if I were to say anything, it would be that collaboration, which we have learned is essential for success this year, it will continue being essential going forward. And so, for any infection preventionists who are thinking about or are reviewing the need for VHP sometime in the future, just know that those colleagues that we’ve relied on this time around are going to be there and are going to be your partners in the VHP process.

ICT®: You were part of a study team and a study team has a very methodical way of doing things. But in the real world, if someone isn’t told that they’re in charge of something, wouldn’t that make it a bit haphazard?

Yen: I think that the folks at our institution who will be choosing or picking VHP…this speaks for general hospitals. They will probably be in the setting where an incident command structure will be in place. There will be a structure and an order to who will be taking points, and which partners will be involved in setting up a process like this. This is definitely not an isolated process, no matter how big or small your hospital is. No matter how many hospitals.

ICT®: Is there anything I neglected to ask you about this, Doctor Yen, that you think is pertinent and that my audience should know about?

Yen: I think one thing that I would love to let folks know is that amongst the many methods that we all explore, for N95 respirator use and reuse, this was but one. And I think it’s important to also note in our study that while we did do multiple cycles, that the FDA emergency use authorization for VHP did change from the time in which our study was started to the current day. So as a people, the current recommendations on the FDA emergency use authorization for VHP, if you were to use it, now it’s set at five cycles. At the time when we did it, back in August and July, it was at 20 or 25 cycles. So, it is a little different now and always remember to check your EUA first before you pursue or before you jump onto one of these technologies.

This interview has been edited for clarity and length.

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