Buzz
Since the early stages of the pandemic, it’s been known that wearing a mask helps protect others from the wearer’s respiratory droplets. But do masks also protect the person wearing them? While the science wasn’t clear at first, the evidence now suggests that they do. The CDC has recently updated their mask guidelines to indicate that the protection appears to work in both directions.
According to the CDC:
Masks also help limit the wearer’s inhalation of droplets (“filtration for personal protection”). The overall benefit of mask-wearing for controlling SARS-CoV-2 arises from the combination of these factors; individual protection increases as more people wear masks consistently and correctly.
This understanding doesn’t alter the core message—we all need to wear masks when interacting with people outside our household—but it does help to understand the source of the protection.
For instance, if you’re going to a place where many people won’t be wearing masks, does it still matter if you wear one? If masks only protect others from you, then you'd be doing a favor for others but not helping yourself. However, if the updated understanding is correct, wearing a mask in that situation likely provides protection for you as well.
What changed?
First, researchers have been investigating the specifics of how masks work, such as how droplets behave when they encounter various mask materials. Droplets can adhere to fibers, be pushed away, or get trapped between them. Even small particles can be captured by masks. (There’s an insightful visualization of how this works at the New York Times.) This supports the idea that masks offer protection no matter which direction the virus-laden particles are coming from.
Another line of evidence comes from case studies conducted in areas where you’d expect high virus transmission, but where widespread mask usage kept transmission rates particularly low. These studies include hairstylists who worked while symptomatic and an outbreak aboard an aircraft carrier. While we can’t definitively determine how much protection came from the wearer's mask versus others' masks, these studies add to our understanding that more masks contribute to a safer environment.
The key takeaway is that masks are effective, even though they're not flawless. N95 masks outperform cloth masks, but many cloth masks remain highly effective depending on their design. (More layers and higher thread counts tend to result in more protective masks.) So, continue wearing your mask, even if others aren’t; it will still make a difference.
