While the evidence is conflicting, some studies suggest healthy people do limit their chances of infection if wearing a face mask, especially properly fitted N95 or N100 respirators.
With 663,828 reported COVID-19 cases across 177 countries and territories as of March 28, 2020, and no known cure, people are seeking ways to protect themselves against infection. Logically, many are resorting to wearing face masks when venturing out in public.
However, as face masks are becoming harder to come by, health experts are issuing public statements saying the masks won’t protect healthy people against infection.
Is that true? Or is it a ploy to ensure an adequate supply for health care workers? As reported in a March 4, 2020, Time article:
“‘It seems kind of intuitively obvious that if you put something — whether it’s a scarf or a mask — in front of your nose and mouth, that will filter out some of these viruses that are floating around out there,’ says Dr. William Schaffner, professor of medicine in the division of infectious diseases at Vanderbilt University.
The only problem: that’s not effective against respiratory illnesses like the flu and COVID-19. If it were, ‘the CDC would have recommended it years ago,’ he says. ‘It doesn’t, because it makes science-based recommendations.'”
Do Masks Only Protect Health Care Workers?
According to the U.S. Centers for Disease Control and Prevention, surgical masks are not designed to provide protection against airborne pathogens and are not considered respiratory protection. They’re only designed to prevent large-particle droplets (which may contain pathogens) from reaching your mouth and nose.
Part of the problem is that these kinds of masks won’t form a seal around your face. Most people also have a tendency to touch their face a lot, thus depositing pathogens from their hands to their face anyway.
According to U.S. Surgeon General Dr. Jerome Adams, wearing a mask may actually increase your risk of infection, as most people will touch their face even more frequently when wearing one. The CDC only recommends surgical masks for:
- People who are symptomatic, as the mask will inhibit the spread of the virus if you cough or sneeze into the mask
- Caregivers for infected patients
Mayo Clinic infectious diseases specialist Dr. Nipunie Rajapakse explains:
“The current recommendations regarding masks are that if you yourself are sick with fever and cough, you can wear a surgical mask to prevent transmission to other people.
If you are healthy, there is not thought to be any additional benefit to wearing a mask yourself because the mask is not airtight and does not necessarily prevent breathing in of these viral particles, which are very tiny.”
What About N95 Respirators?
The CDC also does not recommend that the general public wear N95 respirators, which are designed to be tight-fitting and capable of filtering out at least 95% of much smaller (0.3 micron in size) airborne particles. According to the U.S. Food and Drug Administration:
“For the general American public, there is no added health benefit to wear a respiratory protective device (such as an N95 respirator), and the immediate health risk from COVID-19 is considered low.”
You wouldn’t think the health risk from COVID-19 was “considered low” by looking at or listening to the news though. Perhaps journalists didn’t get the memo?
Either way, it strikes many as odd that facemasks and N95 respirators are universally considered key instruments for infection control in health care settings, yet the general public is now told they won’t protect against respiratory diseases such as COVID-19.
The Respirator Fit Test
One reason cited for why the public should not use N95 respirator masks either, even though they protect against airborne pathogens, is because they require fit testing to ensure a tight seal around the face.
However, according to the CDC’s fit test Q & A document, this is a relatively simple affair. The qualitative pass/fail test that an individual would conduct to assess whether the mask is properly fitted is a smell test. If you can smell an odorous substance through the mask, it’s not tight-fitting enough.
What’s more, this test only needs to be done once, when selecting the best-fitting brand, make, model and size of the respirator. Once you know which model fits your face best, you don’t need to do the fit test again until or unless your facial structure changes due to dental or cosmetic surgery, for example, or “an obvious change in body weight.” Health care workers, however, must do the fit test once a year regardless, in order to maintain NIOSH compliance.
What Does the Research Say?
So, what’s the real deal on the use of face masks? Do they only protect health care workers from getting sick, and sick patients from spreading it to others, or might they prevent healthy lay people from being infected as well? A 2009 study in Emerging Infectious Diseases sought to answer this question in the wake of the bird flu (H5N1) outbreak. According to the authors:
“Many countries are stockpiling face masks … to reduce viral transmission during an influenza pandemic. We conducted a prospective cluster-randomized trial comparing surgical masks, non–fit-tested P2 masks, and no masks in prevention of influenza-like illness (ILI) in households.
During the 2006 and 2007 winter seasons, 286 exposed adults from 143 households who had been exposed to a child with clinical respiratory illness were recruited … Adherence to mask use was associated with a significantly reduced risk of ILI-associated infection.
We concluded that household use of masks is associated with low adherence and is ineffective in controlling seasonal ILI. If adherence were greater, mask use might reduce transmission during a severe influenza pandemic.”
In other words, mask use was ineffective due to low adherence, not because they don’t prevent the transmission of illness. In fact, were more people to wear masks, infection rates would probably be lower.
Face Masks ‘Underappreciated’ for Infectious Control
Then there’s the article “Disrupting the Transmission of Influenza A: Face Masks and Ultraviolet Light as Control Measures,” published in Health Policy and Ethics in 2007, which states:
“In the event of an influenza pandemic, where effective vaccine and antiviral drugs may be lacking, disrupting environmental transmission of the influenza virus will be the only viable strategy to protect the public. We discuss two such modalities, respirators (face masks) and ultraviolet (UV) light.
Largely overlooked, the potential utility of each is under appreciated. The effectiveness of disposable face masks may be increased by sealing the edges of the mask to the face. Reusable masks should be stockpiled, because the supply of disposable masks will likely prove inadequate …
Respirators (N–95 and N–100; both commercially available) are masks designed to shield the wearer from inhalational hazards, as opposed to surgical masks, which are designed to protect others from contaminants generated by the wearer. In the discussion that follows, use of the word mask refers only to the former …
Current respirator filters are typically made of polypropylene wool felt, or fiberglass paper. Particles collide with and become enmeshed within these non-woven fibers. Another mechanism for the filtering media may be the electrostatic charge that these fibers have, which attract and hold oppositely charged particles. The influenza virus has charges at its hemagglutinin spikes …
N95 respirators … have been reported to be protective in preventing transmission of the severe acute respiratory syndrome (SARS) virus … but use of these masks failed to prevent a cluster of cases in one hospital.
If one assumes that influenza is transmitted by respiratory droplets (… which immediately fall to the ground) rather than by aerosols (… which remain suspended in air for long periods of time), the supposition may be that keeping a safe distance may obviate the need for a face mask.
It is stated that the range of such droplets is generally no more than 3 ft. We are unable to locate the basic science behind that assertion … Laschtschenko found that talking sprayed viable bacteria 6 m (approximately 20ft).
Koeniger … found that even whispering sprayed bacteria … 7.4 m (approximately 24 ft) and a mixture of coughing, speaking, and sneezing carried bacteria 12.4 m (40 ft) … From these very old reports, the distinction between respiratory droplets and aerosols may be more apparent than real.
As a respiratory droplet falls to the ground, the aqueous portion quickly evaporates, but the bacterial or viral portion remains. Theoretically, a viral particle, if it remains viable, could be carried by wind or reaerosolized by ground disturbances.”
The paper does highlight several factors that can render respirator masks unreliable and ineffective. There’s the issue of fit and seal against the face, the fact that they cannot be repeatedly reused, the risk of contact contamination when touching or removing the mask, and the fact that your eyes are also a portal for viral infection.
Still, N95 and N100 respirators “offer the potential of mitigating a potentially uncontrollable pandemic,” the authors note, adding “It is our hope that this brief review … draws the attention of policymakers to allow for wider implementation of their use as public health measures.”