Backgrounder - CDC recommendations: N95 extended use, decontamination and reuse

Extended use and reuse

There is a major shortage of N95 respirators as a result of the COVID-19 pandemic. The US Centers for Disease Prevention and Control (CDC) provides guidelines for extended use and limited reuse of N95. The guidelines recommend a combination of approaches to conserve supplies while safeguarding health care workers in such circumstances. These existing guidelines recommend that health care institutions:

• Minimize the number of individuals who need to use respiratory protection through the preferential use of engineering and administrative controls;
• Use alternatives to N95 respirators (e.g., other classes of filtering facepiece respirators, elastomeric half-mask and full facepiece air purifying respirators, powered air purifying respirators) where feasible;
• Implement practices allowing extended use and/or limited reuse of N95 respirators, when acceptable; and
• Prioritize the use of N95 respirators for those personnel at the highest risk of contracting or experiencing complications of infection.

More detail regarding the third item, extended use and/or limited reuse of N95 respirators:

Extended use refers to the practice of wearing the same N95 respirator for repeated close contact encounters with several patients, without removing the respirator between patient encounters. Extended use may be implemented when multiple patients are infected with COVID-19 and patients are placed together in dedicated waiting rooms or hospital wards. Extended use has been recommended as an option for conserving respirators during previous respiratory pathogen outbreaks and pandemics.

Extended use is favored over reuse because it is expected to involve less touching of the respirator and therefore less risk of contact transmission. A key consideration for safe extended use, for several hours, is that the respirator must maintain its fit and function.

Healthcare facilities should develop clearly written procedures to advise staff to take the following steps to reduce contact transmission after donning:

• Discard N95 respirators following use during aerosol generating procedures.
• Discard N95 respirators contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
• Discard N95 respirators following close contact with, or exit from, the care area of any patient co-infected with an infectious disease requiring contact precautions.
• Consider use of a cleanable face shield (preferred) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls) to reduce surface contamination.
• Perform hand hygiene with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).

Extended use alone is unlikely to degrade respiratory protection. However, healthcare facilities should develop clearly written procedures to advise staff to:

• Discard any respirator that is obviously damaged or becomes hard to breathe through.

Reuse refers to the practice of using the same N95 respirator for multiple encounters with patients but removing it (‘doffing’) after each encounter. The respirator is stored in between encounters to be put on again (‘donned’) prior to the next encounter with a patient. For pathogens in which contact transmission (e.g., fomites) is not a concern, non-emergency reuse has been practiced for decades. Even when N95 respirator reuse is practiced or recommended, restrictions are in place which limit the number of times the same FFR is reused. Limited reuse has been recommended and widely used as an option for conserving respirators during previous respiratory pathogen outbreaks and pandemics.

Healthcare facilities should develop clearly written procedures to advise staff to take the following steps to reduce contact transmission:

• All the steps listed above to reduce contact transmission for extended use are also important for reuse.
• Hang used respirators in a designated storage area or keep them in a clean, breathable container such as a paper bag between uses. To minimize potential cross-contamination, store respirators so that they do not touch each other and the person using the respirator is clearly identified. Storage containers should be disposed of or cleaned regularly.
• Avoid touching the inside of the respirator. If inadvertent contact is made with the inside of the respirator, discard the respirator and perform hand hygiene as described above.
• Use a pair of clean (non-sterile) gloves when donning a used N95 respirator and performing a user seal check. Discard gloves after the N95 respirator is donned and any adjustments are made to ensure the respirator is sitting comfortably on your face with a good seal.

Please see more details regarding extended use and reuse recommendations in the CDC publication here, including a discussion of the risks of both practices.

Reuse after five days

According to the CDC, one strategy to mitigate the contact transfer of pathogens from the respirator to the wearer during reuse is to issue five respirators to each healthcare worker who may care for patients with suspected or confirmed COVID-19. The healthcare worker will wear one respirator each day and store it in a breathable paper bag at the end of each shift. The order of FFR use should be repeated with a minimum of five days between each FFR use, since the current research indicates the COVID-19 virus will not remain viable for that period. This will result in each worker requiring a minimum of five FFRs, providing that they put on, take off, care for them, and store them properly each day. Healthcare workers should treat the respirator as though they are still contaminated and follow the precautions outlined in the reuse recommendations. If supplies are even more constrained and five respirators are not available for each worker who needs them, decontamination may be necessary (see next).

Decontamination and reuse

We received several emails with concerns over the sterilization, decontamination or disinfection of filtering facepiece respirators, such as N95.

According to the CDC, disposable filtering facepiece respirators (FFRs) are not approved for routine decontamination and reuse as standard of care. However, FFR decontamination and reuse may need to be considered as a crisis capacity strategy to ensure continued availability during the pandemic. Based on the limited research available, three different methods – ultraviolet germicidal irradiation, vaporous hydrogen peroxide, and moist heat –showed the most promise as potential methods to decontaminate FFRs.

Decontamination and subsequent reuse of FFRs should only be practiced as a crisis capacity strategy. At present, FFRs are considered one time use and there are no manufacturer authorized methods for FFR decontamination prior to reuse. Decontamination might cause poorer fit, filtration efficiency, and breathability of disposable FFRs as a result of changes to the filtering material, straps, nose bridge material, or strap attachments of the FFR. CDC does not recommend that FFRs be decontaminated and then reused as standard care. This practice would be inconsistent with their approved use, but we understand in times of crisis, this option may need to be considered when FFR shortages exist.

Research is ongoing. Because ultraviolet germicidal irradiation (UVGI), vaporous hydrogen peroxide (VHP), and moist heat showed the most promise as potential methods to decontaminate FFRs, researchers, decontamination companies, healthcare systems, or individual hospitals should focus current efforts on these technologies.

When information from the manufacturer or a third-party is available showing that respirators can be successfully decontaminated without impacting respirator performance, then FFRs decontaminated following those recommendations can be worn for any patient care activities.

In the absence of guidance or when information is available that a respirator cannot be decontaminated without negatively impacting the performance, respirators may still be decontaminated. However, given the uncertainties on the impact of decontamination on respirator performance, these FFRs should not be worn by HCPs when performing or present for an aerosol-generating procedure.

No current data exists supporting the effectiveness of these decontamination methods. Therefore, even after decontamination, these FFRs should be handled carefully. HCPs should take the following precautionary measures prior to using a decontaminated FFR:

• Clean hands with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the FFR.
• Avoid touching the inside of the FFR.
• Use a pair of clean (non-sterile) gloves when donning and performing a user seal check.
• Visually inspect the FFR to determine if its integrity has been compromised.
• Check that components such as the straps, nose bridge, and nose foam material did not degrade, which can affect the quality of the fit, and seal.

See the CDC publication for more details.