The new advice is to mask up indoors if you live in a place with “substantial” or high virus transmission. (The guidance for people who are unvaccinated remains the same: Always mask up indoors.)
So, what’s the level of transmission where you live? Look up your county below.
The change to CDC’s masking guidelines came after pressure from many outside experts, and — as CDC director Rochelle Walensky said in a press briefing — after new evidence showed delta was more transmissible than previously understood.
“This was not a decision that was taken lightly,” Walensky said, noting that new data from outbreak investigations show that, while it’s rare, vaccinated people can still get infected and spread the virus to others.
“On rare occasions, some vaccinated people infected with the delta variant after vaccination may be contagious and spread the virus to others,” she told reporters when announcing the new guidelines. “This new science is worrisome and, unfortunately, warrants an update to our recommendations.”
The data for this map comes from CDC and is updated regularly. The color-coding is based on two metrics: The number of new cases per 100,000 residents and the percent of coronavirus tests that come back positive in a 7-day period. (A high positivity rate indicates that the number of infections in a place may be high, and that more testing needs to be done.)
If those two metrics show different levels of transmission in a given place, CDC selects the higher level. Nearly two thirds of counties in the country are currently experiencing substantial or high transmission as of late July.
CDC classifies a community as having “substantial transmission” if there are 50-99 weekly cases per 100,000 residents or if the positivity rate is between 8.0-9.9%. If your county falls into this category, you should wear a mask indoors, whether or not you are vaccinated. CDC also advises on its website that “everyday activities should be limited to reduce spread and protect the health care system.”
A county has “high transmission” if it has anything over 100 weekly cases per 100,000 residents or 10% or greater test positivity rate in the last seven days. In that case, communities should implement universal masking indoors and consider additional “significant measures … to limit contact between persons,” according to CDC’s website.
Health experts suggest that — beyond the level of community transmission — there are other circumstances in which vaccinated people might want to wear masks, for instance if they live with unvaccinated children or have immunocompromised family members, or if they’re going somewhere without good ventilation.
Walensky continues to emphasize the need for more people to get vaccinated, noting that the areas with the lowest vaccination rates are getting hit hardest with this recent wave. “With the delta variant,” she said, “vaccinating more Americans now is more urgent than ever.”