Mandating a clean shave before N95 mask fitting is silly (and potentially dangerous)

This rant only applies to a small portion of the population: those with beards who require protection for airborne pathogens. There is a consistent belief among infectious disease and occupational health workers that one needs to be clean shaven to get fit tested for an N95. That belief is both silly and dangerous. 

Unfortunately, the people who need to read this rant probably never will. Infection control and PPE decisions in most hospitals are as science agnostic as anything in medicine. The people in charge seem to think that a flimsy sheet of paper across an exam stretcher will somehow decrease infections. They think that you need to wash your hands 3 different times before putting on gloves to perform a basic abdominal examination on an immunocompetent patient. They denied that COVID was airborne, refused to let us use N95s, and made absolutely nonsensical statements about what is and is not an “aerosol generating procedure”. So I have absolutely no faith that these words will change anyone’s practice. Mostly this is an angry rant, but for individuals with beards, perhaps there is something in here that you can use to help keep yourself safe. 

Let’s start with the very limited data on this topic. (As a general rule, the stronger the opinion you hear in medicine, the worse the evidence. This is a prime example of that aphorism.)

N95s work

Before getting into the evidence around beards, let me be very clear: I think N95s work. There is no perfect evidence, but I think the best available evidence suggests that N95s protect clinicians against respiratory illnesses, and arguments to the contrary (from the same people who deny me a mask fitting because of a short beard) were asinine. I want to wear a well fitting N95 respirator when caring for patients with airborne diseases like COVID-19.

Fitting might help

A well fit mask just makes sense, so we don’t need a lot of evidence to accept the practice. That being said, it would be nice to have some evidence for a practice that consumes a huge amount of time and effort across the healthcare industry.

As you might expect, there is not a lot of clinical data that mask fitting actually improves outcomes for healthcare workers. That makes sense, given the rarity with which we actually need airborne precautions, the rarity of infection even without protection, the confounding factor of errors in PPE use, and the fact that even an imperfectly fit mask is still highly effective.

Although there are guidelines and standards that mandate mask fitting, it is almost impossible to determine the reasoning for those recommendations, because the standards are not openly published. They appear to be private industry standards only available at a significant cost. I don’t have access to them, and therefore cannot check what science they use to justify their position. (If safety were the real priority, these standards would be available for free to the people whose lives are on the line.) My sense, given what I know about science in general, is that these standards are probably based on expert opinion rather than any real evidence.

There is one retrospective case-control study from COVID that makes the statement that COVID infections were higher among nurses who failed N95 fit testing. (Fujimoto 2025) However, something is very wrong with the numbers they present in their tables. In table 1, the rate of SARS-CoV-2 positivity was 14/111 (13%) in the group that failed their mask fit and 37/154 (24%) in those that passed their fit test. Based on the numbers they present, failing the fit test was protective. I am assuming this is just a transcription error, but it makes the paper hard to trust.

Higher quality data in the form of a cluster RCT with 1441 clinicians finds no real difference between fit-tested and non-fit tested N95s in the prevention of respiratory illnesses, although both look somewhat better than surgical masks. (MacIntyre 2011) As far as I can tell, this is the only RCT on this topic (and OpenEvidence agrees with my search). The key caveats are that infection rates are very low in all groups (potentially leaving the trial underpowered), and that even perfect fitting doesn’t mean perfect use.

I am in favour of mask fitting, but it is worth noting that the evidence for the practice is fairly limited. If you really factored in the cost of these programs, and lost productivity, it is possible that you might end up arguing that fitting programs aren’t worth it. More importantly, the idea that you need an absolutely perfect fit test, when there is such limited data on the value of fitting testing in general, seems like a stretch. But again, let me be clear, despite the limitations in the evidence: I would really like to have a mask fit completed. I just want my mask fit to apply to the way I work (that is, with a beard). 

Beards don’t prevent an adequate fit test

Mask fitting is not perfect. Even without a beard, failed tests are very common. So the simple fact that some people with beards fail fit tests is irrelevant. We need to know how often bearded individuals fail tests as compared to those without beards. Perhaps more importantly, we need to know how often people with beards pass their tests. Most of all, we need to know what the implications of a passed test while clean shaven are for a man who will work shifts (and therefore end up using the mask) with a beard. 

It makes sense that beards would decrease N95 efficacy, but perhaps only marginally. One study found a linear decrease the longer a beard got, but found a fitted filtration efficiency “remaining at or above 95% with beard length of 2.5 mm, equivalent to approximately 7 days of growth”. (Prince 2021) Really, looking at their figures, there is no difference in efficacy out to 10mm beard length:

One study of 28 bearded males, who subsequently shaved for the study, found an identical pass rate when bearded (46%) as compared to being clean shaven (50%). (da Eira Silva 2025) There was also no statistical relationship between the length of the beard and the overall fit factor.

It is very clear that short beards should not be disqualifying from fit testing. Floyd and colleagues found that 98 percent of men with 3 mm (0.125 inch) beards achieved fit factors above 100 (the passing score) on quantitative fit testing. (Floyd 2018) Numbers get worse at longer lengths, but still 81% passed with a beard of 6.5 mm (0.25 inches), and 58% still passed with a beard that was 13 mm (0.5 inches) long. If half of men with long beards can pass the test, it makes no sense to turn them away automatically.

Some studies are hard to interpret, because they do not provide measurements of beards, and it’s not like there is a universally agreed upon definition of “full beard”. No one expects an N95 to be effective for the lead singer of ZZ Top, but modern beards are often short enough to be considered “heavy stubble” in some of these studies. In a widely cited study, Sandaradura and colleagues report that 0% of fully bearded men had successful mask fits as compared to 47% of full shaven men. (Sandaradura 2020) Mask fit guidelines seem to blindly report those numbers, without reading the body of the work, which tells us that men with light stubble pass at a rate of 40%, heavy stubble at 29%, and there is a category of “other”, which they don’t define, but have facial hair that passes at 33%. 

This data makes it incredibly clear that a short beard does not disqualify one from taking (and passing) a fit test. People with short beards pass their fit test at almost the exact same rate as people who are clean shaven. Turning someone away from an important safety test just because of a short beard goes completely against the available science. 

The validity of a clean shaven test for bearded men

Occupational health insists testing should only be done while clean shaven, but people have beards. The result is that many men shave once every 2 years to pass this test, but then return to their bearded status. The most important question is whether this clean shaven test has any validity or value to the man who will have a beard when the N95 is used clinically. 

This is a difficult question to research, but I have rephrased the question hundreds of times in PubMed, Google Scholar, and AI based searches, and as far as I can tell, despite being standard at every hospital, no one has ever studied this approach.

Guidelines seem to say one of two things:

• If a person grows a beard, the fit test is no longer valid and the person should be retested. (But of course, they will refuse to test you with the beard, so I don’t really know what this recommendation means.) 
• Or: the person should remain cleanly shaven for a long as the N95 is required (ie, your entire career).

This guidance is clearly impractical, and not being followed. This is basically the equivalent of preaching abstinence. Forget everything we know about harm reduction. Forget alternative options. Occupational health is black and white: to work in health care, you must not have facial hair.

As a result, men with facial hair are left to work with unproven PPE, ultimately making them less safe. 

The logic

Honestly, the evidence is somewhat irrelevant. The fundamental problem is one of logic. Those demanding men be clean shaven for mask-fitting, when they know they will not be clean shaven while working, are making a grave (and potentially dangerous) logical error. They have failed to understand the concept of internal versus external validity. I don’t need a mask that works only in a rarified occupational health clinic setting. I need a mask that works on shift, when a patient with ebola arrives. On shift, I will have a beard. On shift, there is no time to go home and shave. I need to know that the mask will work with the beard I have every single day. 

The data makes it very clear that N95s can be effective with a (short) beard. The pass rates are almost identical when comparing a short beard to being clean shaven. Personally, I know that is true. In the 20 years since I started medical school, I have undergone 12 mask-fits at many different hospitals, 11 of which were with a beard (although I have been turned away at least as many times). The N95 that I use works perfectly with the beard that I always have.

This information is important. It tells me that I am safe to see patients even while sporting a beard. It allows me to trust my PPE. Refusing to test me because I have facial hair makes me less safe. It strips me of any confidence in my PPE. I don’t need a mask that fits the clean shaven face I will never have. I need a mask that fits me as I actually work. 

Summary

Let me get one thing clear: this is not about vanity. I’m an ugly looking guy with a beard; I look just as silly when I shave it off. I could shave for one week and it would have exactly zero impact on my life. 

This is about my safety. I need a mask that I know will work when used in real world working conditions. I need to be able to go into an Ebola patient’s room with full confidence. A mask that only works when I am perfectly shaven is a mask that might leave me dead. 

Right now, the hospital gives people a check mark, makes them feel better, but then sends them away to unsafe practice. The hospital is prioritizing check marks over safety. 

We clearly should allow and encourage men to get fit for their N95 with whatever beard they will normally sport. The real question is what we should do with those who fail the test. 

One option would be to shave and retake the test. If you pass, you have important information. You know that your beard is interfering with your N95. You can then decide to remain clean shaven, shave just during important infectious disease outbreaks, alter the style of your beard and retest, pursue alternative PPE (such as a PAPR), or just accept the risk. There are also simple, evidence based solutions, such as under-mask beard covers that could be pursued. (Bhatia 2022) What is important is having valid information so people can make informed decisions, rather than simply refusing to test individuals with beards.

If you fail again with a clean shaven face, at least you know the beard wasn’t the problem. In these studies, a large number of people fail, even in the absence of facial hair. Every hospital seems to have a different plan for these people. 

There is lots of uncertainty, but one thing is clear: refusing to perform mask fit tests of people with short beards runs contrary to the available science, and results in a significant increase in risk for those individuals when working clinically. This practice needs to stop immediately.

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References

Bhatia DDS, Bhatia KS, Saluja T, Saluja APS, Thind A, Bamra A, Singh G, Singh N, Clezy K, Dempsey K, Hudson B, Jain S. Under-mask beard covers achieve an adequate seal with tight-fitting disposable respirators using quantitative fit testing. J Hosp Infect. 2022 Oct;128:8-12. doi: 10.1016/j.jhin.2022.05.015. Epub 2022 May 31. PMID: 35662553

da Eira Silva V, Abele M, Bercovitz I, Ferguson S. Preliminary Results on How Longer Facial Hair Lengths May Interfere With N95 Respirator Efficacy: A Brief Report. Workplace Health Saf. 2025 Jul;73(7):358-362. doi: 10.1177/21650799241230039. Epub 2025 Apr 17. PMID: 40247465

Floyd EL, Henry JB, Johnson DL. Influence of facial hair length, coarseness, and areal density on seal leakage of a tight-fitting half-face respirator. J Occup Environ Hyg. 2018 Apr;15(4):334-340. doi: 10.1080/15459624.2017.1416388. PMID: 29283316

Fujimoto G, Obikane S, Kuboyama K. Effectiveness of N95 Mask Fit Testing for the Prevention of Severe Acute Respiratory Syndrome Coronavirus 2: A Retrospective Case-Control Study. Cureus. 2025 Jan 8;17(1):e77168. doi: 10.7759/cureus.77168. PMID: 39925504

MacIntyre CR, Wang Q, Cauchemez S, Seale H, Dwyer DE, Yang P, Shi W, Gao Z, Pang X, Zhang Y, Wang X, Duan W, Rahman B, Ferguson N. 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. 2011 May;5(3):170-9. doi: 10.1111/j.1750-2659.2011.00198.x. Epub 2011 Jan 27. PMID: 21477136

Prince SE, Chen H, Tong H, Berntsen J, Masood S, Zeman KL, Clapp PW, Bennett WD, Samet JM. Assessing the effect of beard hair lengths on face masks used as personal protective equipment during the COVID-19 pandemic. J Expo Sci Environ Epidemiol. 2021 Nov;31(6):953-960. doi: 10.1038/s41370-021-00337-1. Epub 2021 May 18. PMID: 34006963

Sandaradura I, Goeman E, Pontivivo G, Fine E, Gray H, Kerr S, Marriott D, Harkness J, Andresen D. A close shave? Performance of P2/N95 respirators in healthcare workers with facial hair: results of the BEARDS (BEnchmarking Adequate Respiratory DefenceS) study. J Hosp Infect. 2020 Apr;104(4):529-533. doi: 10.1016/j.jhin.2020.01.006. Epub 2020 Jan 21. PMID: 31978416