What we know about the CDC’s new mask mandate

• The Centers for Disease Control and Prevention now officially recommends fully vaccinated Americans wear masks in public indoor places again.

• The decision is a reversal just two months after the agency said that fully vaccinated people do not have to wear masks.

• The Delta variant is highly contagious and even fully vaccinated Americans could be infectious.

The Centers for Disease Control and Prevention is now recommending that fully vaccinated people return to wearing masks in public indoor places, as the Delta variant continues to run rampant across the US.

In a surprising about-face from its decision two months ago, the agency said that regardless of vaccination status, Americans should mask up in areas with “substantial” and “high” transmission of COVID-19.

Who does the CDC mask mandate apply to?

This applies to people living in areas that have had 50 or more new infections per 100,000 residents over the past week. According to CNN, that’s nearly two-thirds of all US counties.

In addition, C.D.C. officials also “recommended universal masking for teachers, staff, students and visitors in schools, regardless of vaccination status and community transmission of the virus,” according to the New York Times.

“This new science is worrisome and, unfortunately, warrants an update to our recommendations,” Dr. Rochelle Walensky, Director of the CDC, said on Tuesday. “The Delta variant is showing every day its willingness to outsmart us, and to be an opportunist in areas where we have not shown a fortified response against it.”

The mask reversal comes after some areas, like Los Angeles County and parts of Cape Cod, recently required residents to wear masks again due to surging numbers of new cases.

Why do fully vaccinated people need to wear masks again?

The spread of the highly transmissible Delta variant, which quickly became the most dominant strain of COVID-19 in the US, convinced health officials to reverse policies set in May, when the agency said people who were fully vaccinated could shed their masks in indoor settings.

However, the Delta variant is causing problems for vaccinated people. The variant now accounts for more than 80% of all cases in the US. It can infect fully vaccinated individuals — and make them infectious. 

Currently, 99% of hospitalizations of COVID-19 patients are among unvaccinated Americans.

“The big concern is that the next variant that might emerge — just potentially a few mutations away — could evade our vaccine,” Walensky said.

Fewer than half of Americans are fully vaccinated against COVID-19, according to data.

Where do you have to wear a mask?

According to the CDC, all students in kindergarten through high school should wear masks when they return for the new school year, including children who have been vaccinated.

The agency reiterated that schools can safely reopen in the fall full-time.

Beyond schools, there hasn’t been much guidance about mask-wearing.

In an interview with NPR, May Chu, a clinical professor of epidemiology at the Colorado School of Public Health, called the mask guidance “subjective and situational” as it all depends on how you assess each situation.

In areas where people cannot maintain six feet of social distancing, people should wear masks, and that includes sitting next to someone at work, regardless of their vaccination status, according to Chu.

Additionally, areas with crowds — like gyms, restaurants, and venues — could also require masks.

Which masks protect against the Delta variant?

Former Food and Drug Administration commissioner Dr. Scott Gottlieb stressed that higher quality masks can better protect you from the Delta variant.

Speaking to CBS’ “Face the Nation” on Sunday, Gottlieb recommended the KN95 mask or N95 mask to offer better protection. While these masks were hard to come by in the beginning of the pandemic, they are easier to get your hands on now.