CDC Now Recommends Double Masking
Doubling masks can improve filtering, and the CDC is now recommending that people double masks or use layered masks and take steps to improve mask fit.
The CDC advises that suitable layering techniques include:
- Wearing a cloth mask over a disposable or surgical mask.
- Wearing a sheet mask made up of several layers of fabric.
They note that duplicating a disposable mask doesn’t really help because the disposable masks fit too loosely. The CDC also cautions against wearing any other masks with the KN95, although it does not state the reason for this.
The CDC guidelines page also states that it is important to make sure the mask fits well. The more layers you use, the easier it will be for air to follow the path of least resistance, seeping through the edges of your mask.
Not all masks are the same
Cloth masks on their own were not and never were the best option for everyone to wear during a pandemic; On the contrary, they were simply the best way to get a lot of masks to a lot of people without having too much of an impact on the supplies needed by medical professionals.
Any mask can be worn on a continuum from “blocks almost everything” (example: a well-fitted N95) to “better than nothing” (loosely tied bandana). Disposable Surgical Masks – Towards the Better End of the Continuum; a cloth mask in two or three layers, probably in the middle. Unfortunately, a year after the start of this pandemic, we have little authoritative research on how to place a given fabric mask on this continuum, but we know that the tighter the weave and the more layers, the better.
This is how we got to the point where double masks are becoming more common. For example, poet Amanda Gorman doubled over at the inauguration (when she was not performing). And Germany is now requiring people to wear an N95 or similar watch when shopping or using public transport.
Why are you suddenly focusing on the best masks?
I would say there are three reasons. First, we now have enough data to know that masks have a good chance of protecting the wearer from small aerosol droplets; they are not only designed to catch the saliva and snot that comes out of the mouth. Second, there was time for supplies to catch up so that medical masks are more affordable than they were last spring. But third, several new variants of the coronavirus seem to be more transmissible than those we know of. This means that we need to be even more vigilant about preventing transmission. Part of this effort is blocking more and fewer droplets. And if you can be more secure, why not?
Just remember that a mask is only as good as it fits, so if you feel (or see in cold weather) your breath coming out at your cheeks or nose, you know you have gaps through which unfiltered air can enter. in and out. Masks also only reduce your risk, but they are not a magical force field, so it is still best to avoid being in closed rooms with people outside your home.
This post was originally published in January 2021 to discuss double masking, and was updated on February 10, 2021 to accommodate explicit CDC guidance.