Seeing people wear a mask in stores, on the street, public transportation, and more is becoming more prominent than ever. Originally, the WHO and the CDC both repeatedly were against many wearing face masks, but on April 3, 2020, the CDC reversed its decision and announced that healthy people should wear masks to help slow the spread and reduce risk of exposure.

In China, an estimated amount of more than 80% of infections with COVID-19 went undocumented and unnoticed. These undocumented cases, while none of the transmitters showed symptoms, still spread COVID-19 everywhere they went. These undocumented cases accounted for over 75% of total transmissions in China.

How Masks Slow the Spread of COVID-19

Masks are utilized to slow the spread of COVID-19 because they can trap contagious particles from an infected individual from spreading. In lab testing, it was found that wearing a face mask could prevent particles from getting through – confirming that a mask can protect others from the wearer.

The reason this works is that a large number of transmissions are passed through asymptomatic carriers. These masks, according to one study, combined with frequently using hand sanitizer, can reduce flu transmissions by up to 50% or more. COVID-19, being estimated at nearly 3 times more contagious, even a small decrease in infection rates could mean a huge difference. Since the creation of the N95 respirator, which proved to be very good at stopping the spread of tuberculosis and other viruses, very little research has been done on cloth masks.

Masks Are Not Worn For Social Reason In the U.S.

Wearing a mask, while becoming more common is still not worn by many for social reasons. “We need to change our perception that masks are only for sick people and that it’s weird or shameful to wear one… If more people donned masks it would become a social norm as well as a public health good” says Robert Hecht, Professor of Clinical Epidemiology in the Yale School of Medicine.

In countries where wearing a face mask is common, like China, Japan, South Korea, and Taiwan, experts noticed that the oncoming spread of COVID-19 was much more controlled because face masks in those countries are more than recommended, they are culturally expected. In the U.S., people of color are afraid of wearing a face mask in public for fear of being mistaken as a robber. On March 18, 2020, a police officer kicked 2 black men out of a Walmart for wearing face coverings.

90% of U.S. Cities Report a Shortage of Face Masks

Nearly 90% of U.S. cities are reporting a shortage of face masks that are needed to protect emergency responders and healthcare workers. Making a face mask at home is a good way to not cut into that already dwindling supply. A study looking at the effectiveness of homemade masks showed that masks made with higher thread count fabrics, finer mesh gauze, and more layers were more effective at filtering particles in the air.

Taking on and off your mask safely is also important. Use hand sanitizer before putting your mask on and after you take it off and while wearing it, avoid touching it or adjusting it.

Learn more about how face masks might be helping to prevent the spread of COVID-19 here.

This article originally appeared on Kivo Daily