CHICAGO (WLS) -- CDC data shows Cook County is now among Illinois counties reporting "substantial" community transmission of COVID-19.
DuPage, McHenry and Will counties were already at the "substantial" level in the Chicago area. Cook, DeKalb, Grundy, Kendall, LaSalle and Boone counties joined them Thursday.
In Indiana, Newton and Jasper counties are at "high" rates of transmission. Racine County in Wisconsin is at the "substantial" level.
As a result, the CDC recommends everyone in those counties start wearing masks indoors again, even if they're vaccinated.
Gov JB Pritzker's office announced Thursday that face coverings will now be required in all state facilities, regardless of vaccination status.
Cook County Health officials say they are ready to enforce a universal mask mandate that would include both vaccinated and unvaccinated people should they need to.
"We are seeing now more than 50 new cases a day per 100,000 population," said Dr. Rachel Rubin, senior medical officer at Cook County Dept. of Public Health. "If things continue to go in the wrong direction, we will be making masking more universally recommended for indoor locations."
Cook County is just days away from announcing a new transportation program that would give residents a free ride to a vaccination site.
"The idea is to make it as easy and as convenient as possible for people to get vaccinated, and there will be some giveaways with that as well," Rubin added.
SEE ALSO | Chicago COVID vaccine map shows how many residents vaccinated by zip code
Many counties in the Chicago area are now having to reconsider mitigations to keep case counts low.
"It's time for caution," said Steve Brandy, public information officer for Will County Health Dept. "That is a reminder that we are far from done here, and the fact that about 80% of these new cases in Will County are connected to the Delta variant."
Across Illinois, the statewide positivity rate is now the highest it's been since April, with hospitalizations also climbing.
State health data also shows close to 48,000 vaccines were administered, which is the largest one-day increase since the increase reported in late June.
"What we need to do now, is the little niches in different parts of the county that have some people that still aren't vaccinated," Brandy said. "That's why we're doing our special effort with community-based organizations."
And the delta variant should be a reason of high concern especially among those unvaccinated
"The fact that about 80% of these new cases in Will County are connected to the Delta variant that tells you, we need to be careful," Brandy said. "Getting vaccinated is still very important because it lessens the chances that you're going to get sick."
WATCH | DuPage Co. recommends indoor masking in public places
There is some encouraging data from DuPage County, where more than 82% of residents 12 and older have received at least one dose of vaccine and 66% are fully vaccinated.
With DuPage County leading the state in vaccinations, the majority of people enjoying a hot summer day in downtown Elmhurst Thursday were not wearing masks. But even that is not enough to keep the county's COVID transmission rate from rising from the "moderate" to the "substantial" category.
"We are up against a virus which has demonstrated persistence in its ability to challenge us yet one more time," said Karen Ayala, executive director of the DuPage County Health Dept.
With that in mind, the county is now recommending everyone wear a mask in public indoor settings regardless of vaccination status. That is a stronger stance than the one the Elmhurst School District 205 adopted at its meeting Wednesday night. After a robust debate, they determined masks are recommended but optional for vaccinated students - for now.
"One of the things we've learned throughout this pandemic is that things change, and they change very rapidly," said Dr. Keisha Campbell, District 205 superintendent.
SEE ALSO | Illinois COVID vaccine map shows how many residents vaccinated by county
In the community, masks remain a controversial issue.
"I think the county recommendation right now is a little strong," DuPage County Board member Pete DiCianni said. "I think it should be up to the individual districts to interpret."
"I think wearing a mask is such a minor consideration, an easy thing to do," Michael Nejman said. "It protects people. It's our civic duty is how I look at it."
Health experts say the increase in COVID transmission is being led by the Delta variant, which they say is twice as easy to transmit.
"The only thing this virus cares about is surviving," Ayala said. "And in order to survive, it is making the necessary changes, which is really to take advantage of people who aren't vaccinated."
CDC COVID-19 Transmission Levels by U.S. County
Map not displaying correctly? Click here to open in a new window.