Respiratory Protection During Outbreaks -Respirators versus Surgical Masks

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Respiratory Protection During Outbreaks -Respirators versus Surgical Masks

[Reprint from Centers for Disease Control and Prevention (CDC) Website Posted on April 9, 2020 by Christopher Coffey, Ph.D; Maryann M. D’Alessandro, PhD; and Jaclyn Krah Cichowicz, MA: https://blogs.cdc.gov/niosh-science-blog/2020/04/09/masks-v-respirators/]

Consistent use of respirators improves protection against respiratory illness

Consistent use of personal protective equipment (PPE) is an important part of the strategy to protect healthcare professionals from inhaling infectious particles, preventing the spread of respiratory infection between healthcare professionals and patients. Two types of devices are most commonly used in the healthcare setting: N95 filtering facepiece respirators (FFRs) and surgical masks (commonly called facemasks). In consideration of the shortage of N95 respirators during this global outbreak of coronavirus disease 2019 (COVID-19), which is thought to be predominantly transmitted by respiratory droplets, it is important to understand the difference between N95 respirators and surgical masks to ensure proper protection and accurate information when possible.

 

When worn by healthcare professionals, FFRs are designed to protect the wearer and surgical masks are designed to protect the patient

When worn properly, FFRs are designed to protect the wearer (e.g., healthcare worker) by removing at least 95% of particles from inhaled air. The National Institute for Occupational Safety and Health (NIOSH) regulates FFRs by using stringent test conditions to evaluate these devices, approving those that meet a minimum filtration efficiency requirement for occupational use. However, to provide this expected level of protection, an FFR must seal to the wearer’s face, without allowing air leaks to pass through gaps between the respirator and the wearer’s skin. FFRs also provide a physical barrier to protect the wearer’s mouth and nose from being touched by contaminated hands or gloves.

Surgical masks, on the other hand, are not specifically designed to protect the wearer from airborne hazards. These devices limit the spread of infectious particles expelled by the wearer. They are used to help protect a sterile field, such as the area surrounding the site of a surgical incision, from contamination by particles expelled by the wearer, such as those generated by coughs or sneezes. Surgical masks also help provide a physical barrier to protect the wearer from splashes, sprays, or contact with contaminated hands. The Food and Drug Administration (FDA) regulates surgical masks. The FDA regulations do not require surgical masks to form a seal against the user’s face or to have a level of filtration that provides the user protection from aerosol exposures.

 

Scientific studies have shown properly-fitted and worn N95 respirators provide greater protection than surgical masks

Recently, there has been discussion whether N95 FFRs or surgical masks should be the recommended minimum level protection for use in healthcare facilities during outbreaks of infectious diseases. Since the results of studies comparing effectiveness of N95 FFRs and surgical masks are inconsistent, it could not be determined if surgical masks provided comparable protection to healthcare professionals as N95 FFRs.1-4 It should be noted that respirators are designed to reduce the wearer’s exposure to airborne particles. Respirators do not make claims regarding disease prevention. To determine the effectiveness of respirators in the workplace, it is important to verify the performance of the respirator and ensure the wearer is protected.5 Laboratory studies have demonstrated that FFRs provide greater protection against aerosols compared with surgical masks6,7; however, the results of clinical studies have been inconclusive.1-4, 8

During times of shortage, it is important to prioritize N95 respirators for aerosol-generating procedures. When the supply chain is restored, facilities with a respiratory protection program should follow established OSHA and CDC guidelines to protect healthcare workers in cases of airborne transmissible diseases, as described in the Hospital Respiratory Protection Program Toolkit.

The Journal of the American Medical Association’s article, “N95 Respirators versus Medical Masks for Preventing Influenza Among Health Care Personnel: A Randomized Clinical Trial (ResPECT),” has sparked additional discussion on the topic of the comparative ability of respirators versus surgical masks to protect healthcare professionals against airborne pathogens, such as influenza virus. Its authors reported that, “among outpatient health care personnel, N95 respirators versus medical masks as worn by participants in this trial resulted in no significant difference in the incidence of laboratory-confirmed influenza.” 8 The study design and setting were described as “a cluster randomized pragmatic effectiveness study conducted at 137 outpatient study sites at 7 U.S. medical centers between September 2011 and May 2015, with final follow-up in June 2016.” Pragmatic studies, such as this one, seek to measure the effectiveness of an intervention under routine clinical conditions.9

The authors identified six limitations to their study.8 One limitation worth highlighting is in response to current discussions and questions about the minimum level of protection to be recommended for healthcare professionals during outbreaks of infectious disease. The authors stated that, “…only two N95 respirator and medical mask models were studied, limiting the ability to generalize about the protectiveness of other models.” Currently, over 500 N95 FFR models are NIOSH-approved for use and approximately 200 surgical mask models are cleared for use by the FDA.

Given the performance standards that regulate respirators, consistency is expected regarding filtration and fit, if used within a program that includes fit testing. However, with no performance requirements for surgical masks regarding the filtration of environmental aerosols and with no fit testing required, there is no expectation of consistency with filtration or fit based upon a sample of less than 1% of the surgical masks cleared by the FDA in the US at the time of publication.

 

Incomplete or inconsistent use of personal protective equipment is commonly reported among healthcare professionals and substantially reduces protection

This continued discussion about the use of respirators versus surgical masks by healthcare professionals highlights a more prominent point, on which no debate is necessary – PPE, respiratory protection included, cannot effectively protect the users if it is not properly and consistently worn.

Inconsistent use of personal protective equipment is commonly reported among healthcare professionals and substantially reduces protection.12 Unfortunately, observational studies have shown that healthcare professionals frequently do not put on or remove respirators correctly, take their respirators off when they should be wearing them, or do not wear them at all.13,14

For example, the ResPECT study authors also noted that approximately 35% of healthcare professionals reported using respirators or surgical masks only “sometimes” or “never.” According to the authors, incomplete adherence to using respirators or surgical masks “could have contributed to more unprotected exposures, increasing the probability of finding no difference between interventions even if a difference existed.”

 

Adherence to infection control recommendations can be bolstered with training, observation, metrics, and reinforcing safety culture

Although the ResPECT study cannot definitively determine whether there is any practical difference in the protection provided by N95 respirators versus surgical masks, it emphasizes an important opportunity for prevention—improving adherence to infection control recommendations by enhancing safety culture.

Improving safety culture begins with understanding and addressing the many reasons for non-compliance. For example, compliance with proper PPE use improves depending on the level of health risk the worker perceives, such as influenza exposure verses tuberculosis (TB) or the Ebola virus.12 Therefore, establishing a safety culture that emphasizes training and worker safety every day is imperative for consistent compliance. These behaviors can be bolstered with training, observation, metrics, and by reinforcing safety culture.

NIOSH elaborates on this understanding that routine compliance increases preparedness during a public health emergency in the Hospital Respiratory Protection Program Toolkit. Additional resources are available below. Healthcare personnel should be mindful of best practices when implementing respiratory protection program policies as they balance their own safety with other factors associated with patient care in the context of a comprehensive infection control program.

CDC respirator use guidance for healthcare professionals for COVID-19: https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirators-strategy/index.html

 

Christopher Coffey, Ph.D, is the former Associate Director for Science for the NIOSH National Personal Protective Technology Laboratory. (retired)

Maryann M. D’Alessandro, PhD, is the Director of the NIOSH National Personal Protective Technology Laboratory.

Jaclyn Krah Cichowicz, MA, is a Health Communications Specialist in the in the NIOSH National Personal Protective Technology Laboratory.

 

Other Sources of Information

Blogs

Infographics

Factsheets

 

The Centers for Disease Control and Prevention is addressing questions related to the Coronavirus Disease 2019 through CDC-INFO and on their webpage. As such, this blog has been closed to comments. Please visit https://www.cdc.gov/coronavirus/2019-ncov/index.html. You can find the most up-to-date information on the outbreak and get the latest answers to frequently asked questions. If you have specific inquiries, please contact CDC-INFO at https://wwwn.cdc.gov/dcs/contactus/form or by calling 800-232-4636. If you have questions about PPE that are not related to Coronavirus Disease 2019, please contact us at PPEConcerns@cdc.gov.

References

  1. MacIntyre C.R., Q. Wang, H. Seale, P, et al.: A randomized clinical trial of three options for N95 respirators and medical masks in health workers. Am J Respir Crit Care Med.;187(9):960-6 (2013).
  2. MacIntyre C.R., Q. Wang, S. Cauchemez et al.: A cluster randomized clinical trial comparing fit-tested and non-fit-tested N95 respirators to medical masks to prevent respiratory virus infection in health care workers. Influenza Other Respir. Viruses; 5(3);170-179 (2011).
  3. MacIntyre C.R., A.A. Chughtai, B. Rahman et. al. The efficacy of medical masks and respirators against respiratory infection in healthcare workers. Influenza Other Respir. Viruses; 11(6):511-517 (2017).
  4. Loeb, M., N. Dafoe, J. Mahony, et al. Surgical mask vs. N95 respirator for preventing influenza among health care workers: A randomized trial. JAMA 302(17):1865-1871 (2009).
  5. Janssen L, Z. Zhuang, R. Shaffer. Criteria for the collection of useful respirator performance data in the workplace. J Occup Environ Hyg. 2014;11(4):218-226.
  6. Oberg T., L.M. Brosseau. Surgical mask filter and fit performance. Am J Infect Control. 2008; 36(4):276-282.
  7. Rengasamy S et al. Filtration performance of FDA-cleared high filtration surgical masks. JISRP, 2009; 26(Spring-Summer):54-70.
  8. Radonovich L.J. Jr, M.S. Simberkoff, M.T. Bessesen et al. N95 Respirators vs Medical Masks for Preventing Influenza Among Health Care Personnel: A Randomized Clinical Trial. JAMA.;322(9):824-833 (2019).
  9. Roland M., D.J. Torgerson. Understanding controlled clinical trials: What are pragmatic trials? Clinical Review. BMJ 1998; 316:285. see https://www.bmj.com/content/316/7127/285
  10. McDiarmid M., R. Harrison, M. Nicas. N95 Respirators vs Medical Masks in Outpatient Settings. 2020;323(8):789. doi:10.1001/jama.2019.20905
  11. Radonovich R., M, Simberkoff, T. Perl. N95 Respirators vs Medical Masks in Outpatient Settings-Reply. 2020;323(8):789-790. doi:10.1001/jama.2019.20908
  12. ANSI/ASSE Z88.2 (2015) Practices for Respiratory Protection, and ANSI/ASTM F3387 − 19 (2019) Standard Practice for Respiratory Protection.
  13. Beckman S., B. Materna, S. Goldmacher, J. Zipprich, M. D’Alessandro, D.A. Novak, et al. Evaluation of respiratory protection programs and practices in California hospitals during the 2009-2010 H1N1 influenza pandemic. Am J Infect Control. 2013;41(11):1024-31. doi:10.1016/j.ajic.2013.05.006
  14. Benson SM, D.A. Novak, M.J. OGG. Proper Use of Surgical N95 Respirators and Surgical Masks in the OR. AORN Journal. 2013; 97(4):457-470.

 

Posted on  by Christopher Coffey, Ph.D; Maryann M. D’Alessandro, PhD; and Jaclyn Krah Cichowicz, MA

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