PERSONAL PROTECTIVE equipment (PPE) is one of many safety measures used to protect healthcare professionals and prevent the transmission of COVID-19. Other strategies include administrative protocols to change the way that individuals work and engineering controls to isolate individuals from hazards.1,2 The COVID-19 pandemic resulted in increased demand for PPE while the available inventory disappeared initially, causing healthcare professionals to seek alternatives. The CDC recommends respiratory protection with an N95 respirator or equivalent, or a higher-level respirator, for healthcare staff caring for patients with confirmed or suspected COVID-19.3,4
Wearing respiratory protection such as a respirator helps nurses and other healthcare professionals reduce their risk of infection as they care for patients with suspected or confirmed COVID-19. These professionals also wear face masks at other times in the healthcare facility as a universal prevention measure to reduce respiratory secretions while talking, sneezing, or coughing (source control).3 This article offers an overview of CDC strategies for respiratory protection, as well as recommendations from other advisory or regulatory agencies. Healthcare professionals should also check recommendations provided by state, local, or territorial health departments.
Respirators and respiratory protection
A respirator is piece of PPE worn on the face or head that covers at least the nose and mouth. Depending on which type of air-purifying respirator (APR) is used, respirators can reduce the wearer's risk of inhaling hazardous airborne particles such as infectious agents, gases, or vapors.5 Filtering facepiece respirators (FFRs), which represent one type of APR, are disposable.5-7 N95 respirators are the most common disposable respirators. The term “N95” is sometimes used to refer to any disposable respirator such as N99 or N100 respirators.7 In this article, “N95” refers to any disposable respirator with at least 95% filtering efficiency and equivalency.
APRs such as elastomeric half- and full-facepiece respirators are also reusable. Equipped with the appropriate cartridge or filter, they can also be used to protect against gases, vapors, or particles.5,8
Respirators used in healthcare settings are certified by the CDC's National Institute for Occupational Safety & Health (NIOSH).3,7,9 The FDA evaluates and approves PPE such as surgical masks for their degree of protection against the splash and/or splatter of blood and body fluids. These organizations collaborate on the approval of surgical N95 respirators, which filter air and protect against fluid penetration.
According to Occupational Safety and Health Administration (OSHA) respiratory protection standards, respirators must be used within the context of a comprehensive, written respiratory protection program, and individuals should be medically evaluated to ensure they can wear a respirator.10,11 If a respirator becomes soiled or contaminated, it should be discarded (if disposable) or cleaned and decontaminated (if reusable). Similarly, respirators must be discarded or changed if the structural integrity is damaged, resulting in a failed seal check, or if the respirator is difficult to breathe through.10 Wearing a face shield over the N95 or other respirator helps protect it from surface contamination.2,6
Additionally, certain respirators must be fit-tested to determine the appropriate size, brand, and model.10 Fit-testing is specific to the manufacturer brand and model, as design and style may vary. Individuals donning a respirator should also perform a seal check each time per manufacturer instructions.10,12 During the COVID-19 pandemic, OSHA issued temporary enforcement guidance related to the requirement for initial and annual fit testing due to shortages of N95 respirators.13,14 Now that N95s are readily available, fit testing is once again required.
Respirators during the COVID-19 pandemic
When outbreaks or pandemics occur, the demand for PPE increases and may exceed the supply, including the ability to replenish the inventory. The CDC provided recommendations for optimizing PPE supplies in a stepwise continuum of actions moving from conventional capacity to contingency capacity to crisis capacity strategies for implementation during periods of shortages (See Conventional-to-crisis PPE practices).2,15 Healthcare facilities should continually assess PPE needs and inventory and may consider contingency or crisis strategies when they cannot maintain conventional PPE utilization. Once availability of NIOSH-approved respirators returns to normal, facilities should resume conventional practices and PPE utilization.2,15
An N95, equivalent, or higher-protection respirator is recommended to protect healthcare professionals caring for patients with suspected or confirmed COVID-19, as well as vaccinated or unvaccinated patients under quarantine based on prolonged exposure to someone with SARS-CoV-2 infection.3,4 When available, respirators are preferred over face masks, especially for situations in which respiratory protection is most important such as during aerosol-generating procedures. Respirators provide a higher level of protection.3,16 Respirators are tight fitting to the face, whereas masks may have gaps at the sides of the face.2,16
Healthcare professionals should also wear a cleanable face shield over the respirator to prevent droplet spray contamination.2,6 Wearing a surgical mask or cloth covering over an N95 to prevent contamination is not approved or recommended by NIOSH, as it is not consistent with the conditions for approval and voids the certification.6
A December 2020 NIOSH technical report summarized the evaluation of 13 FFR models with exhalation valves and concluded that these models provide respiratory protection for the wearer and reduce particle emissions similar to or better than surgical masks and unregulated barrier face coverings.17 Current CDC recommendations note that NIOSH-approved respirators, even with exhalation valves, protect the wearer and also serve as source control because respirators fit closer to the face without any gaps.2,18
Conventionally, disposable respirators are single-use and discarded after each patient encounter or task.2,3 Reusable respirators are cleaned and decontaminated between uses. This was considered a standard practice before the supply shortages experienced during the COVID-19 pandemic. Conventional use strategies work well when supplies are adequate to meet the demand and the product is consistent with the user's fit testing. However, when the supply can no longer meet the demand and/or the availability of respirators is variable, as occurred during the pandemic, healthcare facilities may implement contingency strategies to conserve supplies.1-3,15 Examples to conserve the supply of respirators include extended use by a user or the use of respirators that have exceeded the manufacturer-designated shelf life for fit testing and training purposes to reserve unexpired products for healthcare delivery.
Extended use refers to the practice of wearing the same N95 respirator for repeated close contact encounters with several patients, without removing it between patient encounters. This practice applies to situations where multiple patients are infected with same respiratory pathogen and patients are placed together in dedicated areas. Extended use reduces the number of times a respirator is touched, such as during repeated donning and doffing, and, subsequently, carries less risk of contact transmission and/or self-contamination. N95 respirators should be discarded when removed.2
For effective extended use, respirators must maintain fit and function. If it is compromised, damaged, or becomes difficult to breathe through, the respirator must be discarded. Per NIOSH recommendations in all strategies for use, respirators should be discarded after they are used in aerosol-generating procedures; if they are contaminated with blood, respiratory or nasal secretions, or other body fluids from patients; or after close contact with patients with an infectious disease that requires contact precautions, if the respirator has been touched by a patient, and after the healthcare professional has exited the respective care areas for these patients. Healthcare professionals should also perform hand hygiene before and after touching or adjusting the respirator. While extended use may cause additional discomfort to wearers, it should not be a health risk if they have been medically cleared to wear a respirator.19
Crisis strategies are implemented when the availability of supplies cannot meet the demand for them, leading to shortages.1-3,15,19 The CDC issued a guidance to help determine whether a healthcare facility has reached crisis capacity during a declared public health emergency.19 These strategies were intended for use only during shortages, and facilities should aim to return to conventional strategies as soon as supplies are available.2 Although no longer recommended since supplies are now available, the crisis capacity strategies that may have been implemented during supply shortages include:2,19,20
- limited reuse of respirators
- use of respirators beyond the manufacturer-designated shelf life for healthcare delivery, including those that have not been evaluated by NIOSH
- use of respirators that have not received NIOSH approval but are similar to NIOSH-approved respirators and approved according to the standards of other countries
- prioritizing use of N95 respirators and face masks by activity type.
Limited reuse refers to the use of the same N95 respirator or other FFR for multiple encounters with patients, but doffing it after each encounter.1,2,19 Respirators are subsequently stored between patient encounters to be donned before the next patient is seen. However, limitations and restrictions apply to limited reuse. For example, N95 respirator performance will decrease as it fails to achieve tight seal due to weakened or stretched straps due to hours in use increase and repeated donning and doffing. Limited reuse of respirators, including N95s, is no longer recommended by the CDC as of May 2021.2,19
Limited reuse included the decontamination of N95 respirators with subsequent reuse. The FDA did issue an Emergency Use Authorization with guidance for decontamination of respirators as a crisis capacity strategy during shortages, but this has since been rescinded.19,20 Decontaminated respirators should not be used.
Reusable respirators such as elastomeric respirators are designed for multiple uses by the same individual, with cleaning and decontamination between uses.8,21 They are categorized using the same designation for series and filtration efficiency as disposable respirators.5,7 Elastomeric respirators have replaceable cartridges or filters that protect against gases, vapors, or particles depending on the cartridge or filter.8,21 These can be half-facepiece respirators that cover the nose and mouth or full-facepiece respirators that cover the nose, mouth, and eyes.2,5,17,21
Powered air-purifying respirators (PAPRs) represent another type of APR to protect healthcare professionals who may be exposed to aerosolized pathogens that can cause acute respiratory infections.5,22,23 Tight-fitting PAPRs require fit-testing, but loose-fitting PAPRs do not and can be worn by healthcare professionals for whom fit-testing is not an option, such as those with facial hair.
Due to theoretical concerns related to unfiltered exhaled air and insufficient evidence to support safe use in sterile fields, PAPRs are often banned from use in the OR due to concerns about contamination of the sterile field.24,25
Several simulation studies have compared the efficiency of PAPRs to surgical masks in reducing aerosolized droplet contamination in a sterile field such as the OR and demonstrated that PAPRs produce less colony-forming units of bacteria than surgical masks or surgical N95s.24-27 These studies did not test for potential viral transmission, but they suggest that PAPRs provide protection for healthcare professionals and, depending on the type or style of PAPR, may also serve as a form of source control.
Reusable APRs, whether elastomeric half- or full-facepiece respirators or PAPRs, are used as part of a written respiratory protection program.8 These devices should be issued only to users who are trained to clean, disinfect, and properly store them between uses per manufacturer recommendations.10 An alternative process is to have a central location for disinfection by trained personnel. Tight-fitting respirators require initial and annual fit-testing and a seal check with each use according to manufacturer instructions. All OSHA guidelines and facility respiratory protection programs should apply.
Healthcare professionals should wear an N95 respirator or one that offers equal or greater protection when caring for patients with confirmed or suspected COVID-19, as well as in aerosol-generating procedures performed on these patients. The COVID-19 pandemic created imbalances in supply and demand for respirators, resulting in a continuum of strategies for the use of available respirators during the shortage. When the supply of respirators becomes more readily available, healthcare facilities should resume conventional strategies for utilization of respirators. As more is understood about COVID-19 and products and supplies change, the official recommendations will change. Healthcare professionals should check updated guidelines from the CDC regularly, as well as the available literature and resources from state, local, and territorial advisory and regulatory agencies.
Conventional-to-crisis PPE practices15
Below is a graphic outline of PPE practices according to the CDC.
Source: Centers for Disease Control and Prevention. Summary for healthcare facilities: strategies for optimizing the supply of PPE during shortages. 2020. www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/strategies-optimize-ppe-shortages.html.
1. Centers for Disease Control and Prevention. Summary for healthcare facilities: strategies for optimizing the supply of N95 respirators during the COVID-19 response. 2020. www.cdc.gov/coronavirus/2019-ncov/novel-coronavirus-2019-SupplyChecklist_of-N95-Respirators_COVID-19_4_6_20_num.pdf
2. Centers for Disease Control and Prevention. Strategies for optimizing the supply of N95 respirators. 2021. www.cdc.gov/coronavirus/2019-ncov/hcp/respirators-strategy/index.html
3. Centers for Disease Control and Prevention. Interim infection prevention and control recommendations for healthcare personnel during the coronavirus disease 2019 (COVID-19) pandemic. 2021. www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control-recommendations.html
4. Centers for Disease Control and Prevention. Updated healthcare infection prevention and control recommendations in response to COVID-19 vaccination. 2021. www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control-after-vaccination.html
5. Centers for Disease Control and Prevention. What are air-purifying respirators? 2019. www.cdc.gov/coronavirus/2019-ncov/images/hcp/N95-infographic-What-Are-APR-508.png
6. Powell J, Pollardj, Rottach D, Sinkule E. Considerations for covering N95s to extend use. Centers for Disease Control and Prevention: NIOSH Science Blog. 2020. https://blogs.cdc.gov/niosh-science-blog/2020/06/16/covering-n95s
7. Centers for Disease Control and Prevention. NIOSH-approved particulate filtering facepiece respirators. 2020. www.cdc.gov/niosh/npptl/topics/respirators/disp_part/default.html
8. Centers for Disease Control and Prevention. Elastomeric respirators: strategies during conventional and surge demand situations conventional, contingency, and crisis strategies. 2020. www.cdc.gov/coronavirus/2019-ncov/hcp/elastomeric-respirators-strategy
9. Electronic Code of Federal Regulations. Part 84. Approval of respiratory protective devices. https://ecfr.io/Title-42/Part-84
10. US Department of Labor: Occupational Safety and Health Administration. 1910.134 - Respiratory Protection. 2011. www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.134
11. Occupational Safety and Health Administration. Hospital respiratory protection program toolkit: resources for respirator program administrators. 2015. https://osha.gov/Publications/OSHA3767.pdf
12. National Institute for Occupational Safety and Health. Filtering out confusion: frequently asked questions about respiratory protection. 2018. www.cdc.gov/niosh/docs/2018-130/pdfs/2018-130.pdf
13. Kapust PJ. Temporary enforcement guidance—healthcare respiratory protection annual fit-testing for N95 filtering facepieces during the COVID-19 outbreak. Occupational Safety and Health Administration. 2020. www.osha.gov/memos/2020-03-14/temporary-enforcement-guidance-healthcare-respiratory-protection-annual-fit
14. Kapust PJ. Temporary enforcement guidance — tight-fitting powered air purifying respirators (PAPRs) used during the coronavirus disease 2019 (COVID-19) pandemic. 2020. Occupational Safety and Health Administration. www.osha.gov/memos/2020-10-02/temporary-enforcement-guidance-tight-fitting-powered-air-purifying-respirators
15. Centers for Disease Control and Prevention. Summary for healthcare facilities: strategies for optimizing the supply of PPE during shortages. 2020. www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/strategies-optimize-ppe-shortages.html
16. Centers for Disease Control and Prevention. Understanding the difference. www.cdc.gov/niosh/npptl/pdfs/UnderstandDifferenceInfographic-508.pdf
17. Portnoff L, Schall J, Brannen J, Suhon N, Strickland K, Meyers J. Filtering facepiece respirators with an exhalation valve: measurements of filtration efficiency to evaluate their potential for source control. Centers for Disease Control and Prevention. 2021. www.cdc.gov/niosh/docs/2021-107/default.html
18. Centers for Disease Control and Prevention. Personal protective equipment: questions and answers. 2021. www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html
19. Centers for Disease Control and Prevention. Implementing filtering facepiece respirator (FFR) reuse, including reuse after decontamination, when there are known shortages of N95 respirators. 2020. www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html
21. Greenawald L, Cichowicz JK, D'Alessandro MM. Supplementing the supply of N95s with reusable elastomeric half mask respirators. Centers for Disease Control and Prevention: NIOSH Science Blog. 2020. https://blogs.cdc.gov/niosh-science-blog/2020/09/08/elastomeric
22. Chang JC, Johnson JS, Olmsted RN. Demystifying theoretical concerns involving respirators with exhalation valves during COVID-19 pandemic. Am J Infect Control
23. Centers for Disease Control and Prevention. Considerations for optimizing the supply of powered air-purifying respirators (PAPRs) for healthcare practitioners (HCP). 2020. www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/powered-air-purifying-respirators-strategy.html
24. Church TJ. Bacterial contamination study of loose-fitting power air purifying respirators (PAPR) compared to N-95 FFR and surgical mask, in a simulated sterile environment. Graduate Theses, Dissertations, and Problem Reports. 2019. https://researchrepository.wvu.edu/etd/3901
25. Levin D, Fleisher J, Schoor M, Bose S., Lovich M, Van Lancker HP. Can controlled or powered air purifying respirators be safely used in the operating room during the COVID-19 pandemic? A review article. Anesthesia Patient Safety Foundation. 2020. www.apsf.org/article/can-controlled-or-powered-air-purifying-respirators-be-safely-used-in-the-operating-room-during-the-covid-19-pandemic-a-review-article
26. Howard RA, Lathrop GW, Powell N. Sterile field contamination from powered air-purifying respirators (PAPRs) versus contamination from surgical masks. Am J Infect Control
27. Kim Y, Hale M. Pilot study to examine the use of a powered air purifying respirator (PAPR) in the operating room. Am J Infect Control