Re-use refers to the practice of using the same N95 respirator by one HCP for multiple encounters with different patients but removing it (i.e. doffing) after each encounter. This practice is often referred to as “limited reuse” because restrictions are in place to limit the number of times the same respirator is reused.2 Re-use has been recommended as an option for conserving respirators during previous respiratory pathogen outbreaks and pandemics.
For pathogens for which contact transmission is not a concern, routine limited re-use of single-use disposable respirators has been practiced for decades. For example, for tuberculosis prevention, a respirator classified as disposable can be reused by the same provider as long as the respirator maintains its structural and functional integrity. If reuse must be implemented in times of shortages, HCP could be encouraged to reuse their N95 respirators when caring for patients with tuberculosis disease first. Limited re-use of N95 respirators when caring for patients with SARS-CoV-2 infection might also become necessary. However, it is unknown what the potential contribution of contact transmission is for SARS-CoV-2, and caution should be used.
It is important to consult with the respirator manufacturer regarding the maximum number of donnings or uses they recommend for the N95 respirator model. If no manufacturer guidance is available, data suggest limiting the number of reuses to no more than five uses (five donnings) per device by the same HCP to ensure an adequate respirator performance.3 HCP should always inspect the respirator and perform a seal check upon donning a re-used respirator. For N95 respirators that have been donned more than five times and may need to be re-used again, respiratory protection program managers should consider implementing a qualitative respirator fit performance evaluation. N95 and other disposable respirators should not be shared by multiple HCP.
During times of crisis, practicing limited re-use while also implementing extended use can be considered. If limited re-use is practiced on top of extended use, caution should be used to minimize self-contamination and degradation of the respirator. If no manufacturer guidance is available, a reasonable limitation should continue to be five total donnings regardless of the number of hours the respirator is worn.
It may also be necessary to re-use N95 respirators when caring for patients with varicella or measles, although contact transmission poses a risk to HCP who implement this practice. Ideally, N95 respirators should not be re-used by HCP who care for patients with SARS-CoV-2 infection then care for other patients with varicella, measles, and tuberculosis, and vice versa.
Respirators soiled or grossly contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients should be discarded. HCP can consider using a face shield or facemask over the respirator to reduce/prevent contamination of the N95 respirator, especially during aerosol generating procedures or procedures anticipated to generate splashes and sprays. It is important to perform hand hygiene before and after the previously worn N95 respirator is donned or adjusted.
The surfaces of a properly donned and functioning NIOSH-approved N95 respirator will become contaminated with pathogens while filtering the inhalation air of the wearer during exposures to pathogen laden aerosols. The pathogens on the filter materials of the respirator may be transferred to the wearer upon contact with the respirator during activities such as adjusting the respirator, improper doffing of the respirator, or when performing a user-seal check when redonning a previously worn respirator. One potentially effective strategy to mitigate the contact transfer of pathogens from the respirator to the wearer could be to issue each HCP who may be exposed to patients with SARS-CoV-2 infection a minimum of five respirators. Each respirator will be used on a particular day and stored in a breathable paper bag until the next week. This will result in each worker requiring a minimum of five N95 respirators if they put on, take off, care for them, and store them properly each day. This amount of time in between uses should exceed the 72 hour expected survival time for SARS-CoV-2 (the virus that causes COVID-19).4 If this strategy is used, the total number of donnings should still not exceed five times before discarding the respirator, when no manufacturer instructions are provided to indicate otherwise. For N95 respirators that have been donned more than five times and may need to be re-used again, respiratory protection program managers should consider implementing a qualitative respirator fit performance evaluation.
If supplies are even more constrained, and five respirators are not available for each worker who needs them, N95 respirator limited re-use with respirator decontamination may be considered. Decontamination is a process to reduce the number of pathogens on used filtering facepiece respirators before re-using them. It is used to limit the risk of self-contamination. Decontamination of NIOSH-approved N95 respirators is not consistent with their approved use. Respirator manufacturers may provide guidance for respirator decontamination. The FDA has issued multiple Emergency Use Authorizationsexternal icon to permit the use of certain N95 respirator decontamination systems during the COVID-19 pandemic. Decontamination may cause poorer fit and reduced filtration efficiency as a result of changes to the filtering material, straps, nose bridge material, or strap attachments of the filtering facepiece respirators and will not increase the number of times (five donnings if not otherwise specified by the manufacturer) that an N95 respirator can be worn. See additional considerations on re-use and potential methods of decontamination.