Are Cloth Masks Safe? - Public Service Announcement
We all wear masks, metaphorically speaking....well these days- it's literal. Today- we all wear masks, period end of sentence.
There are many different types of masks. From dust masks to surgical masks and respirators but today since we all have to wear some type of mask let's take a closer look and we ask the question:
Are Cloth Masks Safe?
I don't know about you- but since we have been in masks for months there is one thing for sure...not all masks are created equal. Some are comfortable, some are poorly made and break on removal and some make you basically feel like you're being suffocated or smothered.
More and more we are seeing people in cloth masks. Now, in all fairness I saw a few camo pattern cloth masks at the store that I bought and well let me tell you: When it comes to comfort and breathability- nothing compares. BUT...and it's a big BUT. Because I often find myself questioning- Are cloth masks safe? Does a cloth mask have the same efficacy of a surgical mask? Is there an advantage to a washable cloth face mask?
I mean after all we are all just trying to stay safe and healthy (despite desiring comfort and decor).
Numbers Don't Lie
There was a randomized controlled study done in Vietnam trying to answer whether or not cloth masks are as safe as a medical mask. In fact, in this study the hypothesis was that there was no difference between cloth masks and medical masks. Assuming we are perhaps safe in any mask. However, the results show some really important things to consider.
"The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks." (1)
Here is a summary:
The study involved 1000+ HCW or health care workers in a controlled setting. When determining the efficacy or effectiveness of one type of mask over the other scientists and doctors considered these 3 metrics:
- CRI or Clinical Respiratory Illness
- ILI or Influenza-like Illness
- Laboratory confirmed virus infection
Based on the test one of the masks would either show more, the same or less CRI/ILI than the other. Well, that's just what happened and we should all be paying attention to the results.
PSA: CLOTH MASKS ARE NOT AS SAFE AS MEDICAL MASKS.
The study showed the following results:
- The rate of ALL infection metrics were highest in the cloth masks
- Cloth masks have higher rates of influenza-like symptoms
- Penetration of particles were as high as 97% in cloth masks. 44% in medical masks.
- Moisture retention and poor filtration in cloth masks may be the cause.
The Particle Party
Last week we took a look at KN95 masks for coronavirus and N95 masks for coronavirus and compared them. You can read that blog post here. Basically we reported that there were some differences between KN95 and N95 masks- mainly the standards and testing.
We also revealed that almost all KN95 masks for coronavirus and N95 as well were made in China and how the Chinese standards and American standards are very much alike. I've been grappling with this because I've always felt that medical or surgical masks were safest. Now it should be said that this study was focused on healthcare workers in a hospital. However, the 3% filtration problem stands out to me. N95 masks and KN95 masks for coronavirus have to filter out at least 95% of particulate to be labeled as such. The cloth masks let in over 97% of particles!
Now, I can understand the appeal of having an American made washable cloth face mask especially in what is now being branded the "Chinavirus". But ultimately you have to consider that we are trying to protect ourselves from a global pandemic. It turns out there is no substitution for rigorous testing and safety standards. So, unfortunately your neighbor's homespun masks are a no go- they just don't have the same level of filtration or protection.
Cloth masks are a reasonable option to decrease high speed droplets which infected patients spew during a cough or sneeze. That's where their utility lies...but to protect those not yet infected....3-ply disposable masks and KN95s are far superior....they reduce infection by about 93% compared to cloth masks. Simply put, the cloth masks are just not as effective.
Macintyre, Chandini & Seale, Holly & Tham, Dung & Hien, Nguyen & Nga, Phan & Chughtai, Abrar & Rahman, Md & Dwyer, Dominic & Wang, Quanyi. (2015). A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. BMJ open. 5. e006577. 10.1136/bmjopen-2014-006577.