As desperate times require desperate measures, many hospitals have adopted reprocessing methods to reuse N95 respirators designed for single use.

A recent study on some of these decontamination techniques revealed respirator efficacy may be compromised if they are reprocessed too often, says lead author of Richard Peltier, PhD, a researcher at the University of Massachusetts Amherst.

“Our results show that some methods of decontamination do cause damage to these respirators. Hospitals need to be vigilant and recognize that this could put clinical workers at increased risk if these mask-damaging processes are used,” he tells Hospital Employee Health. “A few other methods, on the other hand, appear to be safe. Unfortunately, this work tested only a small slice of different preprocessing techniques being used today, and there are many others where there is only limited data showing whether these masks work as designed.”

The researchers found respirators that were treated up to 10 times with specific vaporized hydrogen peroxide (vHP) sterilizers or up to five times with shorter decontamination cycles of gas plasma hydrogen peroxide (gpHP) retain their original filtration capabilities. A decontamination process using ultraviolent germicidal irradiance (UVGI) slowly diminishes filtration efficiency, reaching a level “that warrants caution” after nine repeated treatments, Peltier and colleagues found.1

“Respirator performance is more complex than maintaining fit, and there remains a risk that fundamental aspects of respirators are degraded in a way that limits their performance, even though they retain acceptable fit parameters,” the authors noted.

Respirators ‘Surprisingly Complex’

For the study, N95 respirators were obtained from hospitals using various decontamination techniques. The masks were placed on a mannequin, installed in an exposure chamber, and tested with particle aerosols.

“Respirators are surprisingly complex matrices that can be deleteriously impacted by external forces, such as damaging interaction with strongly oxidizing environments,” they concluded. “While the intent of decontamination is to furnish a sanitized respirator for clinical reuse, some treatments result in respirators that offer less protection to wearers.”

These efforts to reprocess respirators within safe parameters likely will continue as long as healthcare facilities are subject to spot shortages amid the ongoing pandemic. For example, physician offices have largely been left out of the supply chain, the American Medical Association (AMA) emphasized.

Recently, the AMA sent a letter to federal emergency officials, expressing “ongoing concern over the availability of PPE [personal protective equipment], specifically for clinicians in office-based settings.”2

“We understand that PPE and other critical infection control supplies have been directed toward COVID-19 hotspots and to facilities treating infected patients, and we have supported the administration’s efforts to send supplies where they are most needed,” the AMA wrote. “However, as non-hospital-based physicians return to work and reopen their practices, the need for these supplies is rapidly expanding to other care sites.”

While many physician practices have been shuttered in the transition to telemedicine, in-person visits are returning as offices reopen.

“While it is critical to the long-term viability of these practices to resume office visits, the serious threat of COVID-19 infection persists and it is essential that physicians and their staff institute proper infection control protocols and procedures in their practices,” the AMA emphasized. “However, strains on the supply chain for PPE and disinfectant products continue, and they simply are not readily available from the usual sources our physicians use. We are hearing significant and growing concern from our member physicians that they cannot secure needed supplies to safely reopen their practices and that they are unsure where to turn for further guidance and assistance.”

The AMA suggested the Federal Emergency Management Agency create a “clearinghouse on a regional, state, or local level to provide such information to providers in one easy-to-access location.”

Reports of PPE shortages continue in some hard-hit areas, but a lot of manufacturers have increased production of critical items. As different brands and types of equipment are used to bolster stocks, it raises the question of whether staff retraining is needed in some cases. While staying with the same vendor may be preferable, this is a luxury that some hospitals may not be able to afford.

This is a particular concern with respirators that require fit-testing, says Michael Calderwood, MD, MPH, a hospital epidemiologist at Dartmouth-Hitchcock Medical Center in New Hampshire.

“N95s differ quite a bit in their shape and fit, so as we run into supply issues, hospitals may need to bring in different models of these respirators,” he says. “We could run out of one N95 [model] that people have been using for a long time and have been fit-tested with. If we bring something new in, is it similar enough that we assume it has the same fit? Do we need to retest people to make sure that it fits to their face? That is always my concern.”

The choice may be reprocessing the respirators staff are familiar with, or bringing in a new product and retesting.

“A lot of hospitals have been able to reuse respirators with the same efficacy after undergoing decontamination procedures,” he explains. “You have to have in place an ability to look at how well those masks are filtering and [assess] them in terms of fit. Many of the masks come back damaged from general wear and tear, so it does require some infrastructure.”

As hospitals in some areas reopen for elective surgeries, it becomes more critical to keep track of PPE needs in case COVID-19 resurges. Calderwood’s team is using a modeling program to project coronavirus transmission, then bringing in patients who deferred care for other conditions during the pandemic.

“It really had an adverse impact on patients as they waited to get care,” he says. “They may have waited a long time for their surgery, and now they require a more complex procedure. People are being very careful not to do what we had to do the first time — turn everything off.”

Dartmouth’s analytics institute adapted the Penn Medicine COVID-19 Hospital Impact Model for Epidemics to forecast coronavirus activity for the local area out to four weeks.3

“We do our modeling and see if we have enough PPE to handle it,” Calderwood says. “We look at cases both in our healthcare system and in other hospitals in our region. If we see an increase in COVID cases, we have to turn down other activities.”

While modeling may help manage PPE, there is a consensus the medical supply chain must not revert to the lean inventory management systems that left facilities scrambling nationwide when the pandemic hit.

“We learned this very early on,” Calderwood explains. “We had kind of standard use of PPE and had supplies to support a number of days. But of all of a sudden, we were getting into an environment where we needed a lot more PPE.”

A recent analysis of the pandemic by the Massachusetts Institute of Technology Center for Collective Intelligence recommended creating resilient supply chains that include stockpiles of essential equipment and diagnostics — and the ability to ramp up production.4

In the interim, some innovation is required. Hospital clinicians are using creative techniques, including producing their own equipment to meet the outsized demands of treating patients during the novel coronavirus pandemic, the Society for Healthcare Epidemiology of America (SHEA) reports.5

A SHEA survey of its research network hospitals in the United States and Canada revealed methods to maintain safety while preserving supplies and delivering care included:

  • using disposable respirators for more than one day;
  • wearing surgical or cloth masks over respirators to preserve them;
  • storing disposable respirators in a paper bag between uses;
  • reprocessing disposable respirators with vHP, ethylene oxide, UVGI, or moist heat treatments;
  • extending use of disposable gowns;
  • self-producing PPE, test kits, and testing materials.

In April, the SHEA Research Network collected survey responses from healthcare epidemiologists at 69 healthcare facilities, including 58 from the United States and Canada, and 11 located internationally.5

“In the ‘other’ field in a question about self-producing test components, 13% of facilities wrote in that they were self-producing PPE, such as face shields and gowns, due to shortages,” the authors reported. “A quarter of facilities were self-producing testing components, such as swabs, transport media, and collection tubes.”

The survey did not assess the time and resources required to research and implement these tactics.

“However, the burden of doing this across settings, types of procedures, patients, healthcare roles, and local circumstances represents substantial opportunity cost at a time when healthcare facilities were under strain to prepare for, mitigate, and respond to the pandemic,” the authors noted. “These challenges also include implementing unfamiliar practices for HCP, such as long durations of extended use of disposable respirators and gowns.”

In a finding that informs this self-reliant approach, 40% of respondents said their supply of respirators was “limited” or at “crisis level.” Fifteen percent of respondents assessed their supply as “sustainable for the pandemic,” and 45% said it was “adequate for the current situation.”

Two-thirds of facilities reported receiving ethical guidance from their institutions regarding PPE contingency plans, potential therapies for COVID-19, patient triage, equipment modifications, and visitor policies.

“Only about one-third of survey participants had received ethical guidance from states and professional societies in these areas,” the authors reported. “PPE contingency strategies was the topic that facilities said they had most frequently sought and received ethical guidance.”

Regarding testing, 81% of facilities reported access to in-house testing for COVID-19. Among 51 facilities that indicated the turnaround time for COVID-19 diagnostic test results, 43% reported less than six hours, 10% reported a range of seven to 12 hours, 10% reported 13 to 24 hours, and 18% reported longer than 24 hours.

Overall, 26% indicated they self-produced test components due to shortages. Of these, 72% produced viral transport media, 61% made their own viral collection swabs, and 16% produced collection tubes due to shortages. “The vast majority (81%) reported having access to in-house testing for COVID-19,” they concluded. “Sixty-four percent of facilities reported testing asymptomatic patients prior to certain procedures.”


  1. Peltier RE, Wang J, Hollenbeck BL, et al. Addressing decontaminated respirators: Some methods appear to damage mask integrity and protective function. Infect Control Hosp Epidemiol 2020;1-3.
  2. American Medical Association. Letter to the Federal Emergency Management Agency, June 30, 2020.
  3. Penn Medicine. COVID-19 Hospital Impact Model for Epidemics (CHIME).
  4. Kong DS. Pandemic supermind activation: First findings. MIT Center for Collective Intelligence.
  5. Calderwood MS, Deloney VM, Anderson D, et al. Policies and practices of SHEA Research Network hospitals during the COVID-19 pandemic. Infect Control Hosp Epidemiol 2020;1-9.