Are cloths Masks Effective?

Amid the COVID-19 crisis, the CDC and other organizations have done something that’s never been done before: recommended the use of cloth face masks. This is something hotly contested—often utterly dismissed—by the medical community. Granted, the CDC’s recommendation for cloth masks seems to be aimed at the general public as opposed to healthcare providers…but if the goal is to prevent illness in either case, what is the real story with cloth masks?

The answer unfortunately isn’t as black and white as we’d want. There are different factors that need to be seriously considered, as well as some anecdotal evidence that I think is worth sharing.

I’ll start by talking about the scholarly research on the matter. Faculty of an Australian university conducted a large research study involving 1,600 nurses and doctors that looked into the efficacy of cloth masks (two layers of cotton material) versus disposable medical masks (a typical three-layer surgical mask) in preventing infection. Over the course of 4 weeks, they tracked the incidence of clinical respiratory illness, influenza-like illness (ILI), and laboratory-confirmed respiratory virus infection in the participants. The results: 

“The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm…compared with the medical mask arm.”

They also tested the filtration performance of both the cloth masks and the medical masks, and the results of this were quite discouraging for the cloth mask. They found that 97% of particles were able to penetrate the cloth mask, compared to 44% of particles penetrating the medical mask. This effectively means that a two-layer cotton cloth mask will only stop about 3% of particles from penetrating through the mask.

Aside from this glaring contrast between the cloth masks and medical masks, another interesting factor can be noted from this research. In the trial, there was a third control group who operated under their usual practice, which involved sometimes wearing a medical mask and sometimes wearing no mask. Remarkably, the cloth mask wearers had higher rates of infection than even this group who was sometimes not wearing any mask at all. This could suggest a couple of things—that cloth masks may actually do more harm than good, that medical masks are more effective even when only worn sometimes, or, most likely, a combination of both of these factors.

So what can we conclude from this research study? Well, in my interpretation (and I think it would be hard to argue otherwise), cloth masks are not really worth much of anything in terms of protecting you from getting sick; in fact, they might actually be worse than wearing nothing at all. We can also see that disposable medical masks are a great option for preventing illness. The group wearing medical masks suffered significantly less illness than both the cloth mask group and the control group.

This evidence is pretty damning for the cloth mask, despite its best intentions. But what about wearing a cloth mask when you’re already ill, in an effort to contain your own germs? Well, unfortunately this research is damning for that application as well. The fact that the filtration performance test results of the cloth mask were extremely underwhelming (at 97% ineffectiveness) proves that a cloth mask is not an effective barrier, regardless of whether one is trying to stop infectious particles from coming in or going out.

I wanted to also offer some personal evidence, especially to those businesses trying to make the tough decision about cloth masks versus medical masks for their employees. Our team has heard a few tragic stories from clients about how their efforts to save money by using cloth masks have backfired—sadly, some have had employees get sick despite their best efforts to prevent this by providing cloth masks to everyone, and as a result these companies are losing millions of dollars from the consequences of someone in their facility testing positive for Coronavirus. While we could never say for certain that these people contracted Coronavirus as a result of using cloth masks instead of medical masks, it’s a shockingly tragic event and always results in leadership turning away from cloth masks, and thus I felt it worthwhile to mention this anecdote.

As a healthcare professional myself, I cannot neglect to acknowledge that it is healthcare workers that are by far the most at risk during this pandemic and thus are in the most dire need of adequate protection. With medical-grade masks in short supply, there is certainly a difficult and painful ethical dilemma in whether or not the general public should be purchasing these masks or if they should all be diverted to healthcare facilities. The fact of the matter is though, whether we’re talking about the general public or healthcare workers, the goal is to prevent the spread of illness. So if we’re going to turn to alternative solutions, it’s important that they be effective.

Ultimately, it’s up to each individual or group to decide which precautions they will take in efforts to slow/prevent the spread of disease. With all the chaos and conflicting information about face masks circulating right now, I’ve been approached many times with, “What is your professional opinion?” Well, my opinion lies with the facts. The research I’ve talked about here is one of the most robust studies conducted on the effectiveness of cloth masks, and the results speak for themselves. As appreciative as I am of the wholehearted efforts to help by the many people making cloth masks for healthcare workers or the community, at the same time I’m disappointed in the CDC for using their prolific voice to recommend something that hasn’t been proven to be significantly effective in preventing the spread of illness. Regardless of being in desperate times, health and safety standards should not be dropping to desperate measures without an awareness of the facts and the risks therein, which I feel have been largely neglected to the great consequence of many who feel they are perfectly safe behind a double or even single layer of simple fabric. 

Kailey Lareau, BSN, RN

MacIntyre, C., Seale, H., Dung, T., Hien, N., Nga, P., Chughtai, A., . . . Wang, Q. (2015, April 22). A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. Retrieved May 02, 2020, from 

Disclaimer: This blog provides general information only. It does not provide medical advice nor is it a substitute for the advice of a physician. Persons are advised to always consult their healthcare provider for any specific information about personal health.