COVID-19 Health Alert #28: Guidance for Reuse of N95 Respirators during the COVID-19 Pandemic

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DHS Health Alert Network

COVID-19 Health Alert #28

Guidance for Reuse of N95 Respirators during the COVID-19 Pandemic

Bureau of Communicable Diseases, February 18, 2021


  • Wisconsin DHS recommends that health care organizations limit the reuse of N95 respirators to one respirator per staff member per shift. This is based on accumulating evidence showing that reuse of respirators impacts the fit and overall protection against airborne pathogens.
  • Limiting reuse to one respirator per shift is recommended in Wisconsin as a proxy for the CDC/NIOSH recommendation to discard respirators after no more than five donnings. The practice of discarding respirators after one shift is a preferred strategy because of ease of implementation across diverse health care settings.
  • Seal checks should be performed with each donning of a N95 respirator. If a respirator fails a seal check, it should be discarded regardless of the number of times used.

Dear Colleagues,

As we move into the second year of the COVID pandemic with new, more highly transmissible variants circulating, it is more important than ever to practice appropriate respiratory protection. This includes using fit tested N95 respirators when caring for patients/residents with suspected or confirmed COVID-19.

Many health care facilities continue to implement contingency and crisis capacity measures to manage limited supplies of respirators. Evidence is emerging that shows reuse of respirators can impact their fit and protection. While the filtration of these masks can remain effective, repeated use compromises the integrity of elastic straps and staples that are necessary for ensuring correct placement and the necessary tight-fitting seal.

The National Institute for Occupational Safety and Health (NIOSH) at the CDC recommends that, without specific guidance from the manufacturer or qualitative fit performance evaluation at the local facility level, a respirator should not be reused for more than five donnings per device by the same HCP. DHS reviewed available studies on respirator reuse and consulted with other states and the CDC when determining a reasonable and safe approach for Wisconsin healthcare facilities that are utilizing limited reuse of N95s while operating in crisis capacity.

Based on this review and consultation, DHS recommends that facilities use one respirator per staff member per shift before discarding the used respirators. This practice serves as an acceptable proxy for the “five donnings” rule advised by CDC and NIOSH, and enables easier, more consistent tracking.  

Regardless of the length of time a respirator is worn, there are other situations in which respirators should always be discarded:

  • Failed seal check: It remains essential that HCP perform a seal check with every donning and that if the respirator fails the seal check, it is discarded. That check helps ensure a continued strong seal for respiratory protection no matter how many times it is used or reprocessed.
  • Gross contamination: Respirators soiled or grossly contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients/residents should be discarded. Face shields are a good way to protect the respirator and reduce the contamination from patients/residents while providing eye protection. N95s may also be soiled by personal care items applied to the face such as makeup, lotion, and lip balm.
  • Following aerosol-generating procedures (AGP): Respirators used during AGPs should be discarded afterward due to the inherent contamination risk from droplet sprays and aerosolizing particles that are part of these procedures. AGPs increase the risk of N95 surface contamination, leading to a greater chance of HCP self-inoculation when doffing or adjusting the respirator.

Supply levels remain fluid and DHS encourages all health care facilities to continue evaluating their supplies to determine when decontamination, reuse, and extended use practices can be discontinued. PPE optimization remains a spectrum of options and facilities need to use the strategies that best meet their current supply levels, patient/resident care needs, and HCP needs. When respirators are running low, health care facilities may consider prioritization of N95s and well-fitting facemasks by activity. Facilities are encouraged to review the CDC table that uses activity type, proximity, and whether the patient/resident is masked to determine the appropriate type of mask. 

Facilities that have a process in place for decontamination, which is one of the last resorts for crisis capacity management of N95s, should perform a risk assessment weighing the benefits and risks of this practice. This risk assessment will need to be revisited over time as conditions change. CDC continues to indicate that decontamination will not increase the number of times (five donnings or one shift) that an N95 can be worn unless otherwise specified by the manufacturer.


Ryan Westergaard, MD, PhD, MPH
Chief Medical Officer and State Epidemiologist for Communicable Diseases
Wisconsin Department of Health Services

Jonathan Meiman, MD
Chief Medical Officer and State Epidemiologist for Occupational and Environmental Health
Wisconsin Department of Health Services

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