For many, contracting COVID-19 comes with symptoms that may include a cough, chills, shortness of breath, and loss of taste or smell. The U.S. Centers for Disease Control and Prevention found that a whopping 40 percent of infected people are believed to be asymptomatic carriers of the virus, meaning they’re infected (and likely spreading) the disease without even knowing it. In October, as the U.S. reaches its third surge, a new modeling study finds that universal mask usage (95 percent of the population) could save an estimate 130,000 lives by February 2021.

At face value, it seems like a small saving grace that most individuals who contract the virus—which has infected at least 42 million people worldwide and taken more than 1,150,000  lives—get off scot-free. The problem is people who don’t feel sick may continue to go about their daily schedule of taking walks, going to the grocery store, and visiting the pharmacy without taking the necessary precaution of wearing a mask. When you don’t wear a mask, you put the larger community at risk by increasing the chances of spreading the virus to someone for whom it won’t present asymptomatically.

Even though there have been mixed messages about the efficacy of masks since the advent of COVID-19, many public health organizations, including the CDC and the American Lung Association, say wearing cloth masks (not just surgical masks or N95 respirators) is a key strategy in slowing the spread of the virus. What’s more? A June study found that the virus predominately spreads through the air. Meaning, wearing a mask is, quite literally, the safest thing you can do when you’re not in your house.”The CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies), especially in areas of significant community-based transmission,” says the CDC.

Whether you choose to make your own or purchase one, those guidelines are even more important as researchers learn more about asymptomatic cases. “Honestly, we aren’t sure how helpful these homemade masks and makeshift masks with bandanas and scarves are,” said Sonia Vaidian, MD, assistant medical director of EHE Health, in a recent interview with Well+Good. “But it’s better than nothing, given that there are limited N95 respirators and surgical masks available.”

Even beyond basic safety, covering your nose and mouth in public serves a sign to those surrounding you that we’re all weathering this pandemic together. “‘Mask culture’ fosters a sense of a fate shared, mutual obligation and civic duty,” writes medical anthropologist Christos Lynteris, PhD, for The New York Times. “It brings together people faced with a common threat and helps mitigate one of the secondary dangers posed by an epidemic: anomie, or the breakdown of social norms.”

Originally published May 22, 2020; last updated October 26, 2020.