CHICAGO (CBS) — Mayor Lori Lightfoot on Tuesday warned that the city might be forced to reinstate some COVID-19 restrictions if more people don’t get vaccinated against COVID-19, as the highly contagious delta variant continues to spread nationwide.

“Part of why we’re here today is to emphasize to folks that we’re starting to see this uptick, and we want to get ahead of this before we see a second surge,” Lightfoot said at a City Hall press conference.

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Lightfoot and Chicago Department of Public Health Commissioner Dr. Allison Arwady said COVID cases have been increasing all across the United States in recent weeks, including in Chicago, as the delta variant is becoming the dominant strain of the virus.

“In the last couple of weeks, we have seen a steady rise in our daily case and test positivity rates; an increase that we believe is caused by the highly contagious delta variant of COVID-19,” Lightfoot said.

The mayor said Chicago is now averaging 90 new coronavirus cases per day, compared to a rate as low as 34 cases per day in June. The city’s average positivity rate is up to 1.5%, from a record low of 0.4% in late June.

“If we allow the virus to continue to linger here in Chicago, we will likely see further mutations, some of which our current vaccines may not be able to protect against, and have to reinforce some of the restrictions that have come to infamously define much of 2020 and part of 2021,” Lightfoot said.

Arwady said, while COVID-19 is still reasonably under control in Chicago, that could change if more people don’t get vaccinated, because the delta variant is the most contagious variant of the virus.

“It’s about 50% more contagious than the Alpha variant was, which itself is about 50% more contagious than the sort of O.G, the one originally from Wuhan,” Arwady said.

Lightfoot and Arwady said nearly all of the new cases in Chicago are among people who haven’t been vaccinated, or have had only one dose of the two-dose Moderna or Pfizer vaccines.

Arwady said the best way to prevent the delta variant from spreading to the point the city must reinstate COVID-19 restrictions is for people who haven’t been vaccinated to get their shots.

“I don’t want to wait for delta to get even worse here. We estimate that delta is around 44% of the COVID cases here in Chicago and Illinois,” she said. “By next month, it will be the a majority of cases for sure here in Illinois, just as it already is across the country. So let’s not wait for that, because getting vaccinated now is safe, it’s effective, and it protects you, your family, and your community.”

In Chicago, more than 90% of those who have been hospitalized, and more than 95% of those who have died from COVID-19 are unvaccinated, according to Lightfoot.

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The mayor said experts estimate people who get only one dose of the Pfizer vaccine are about 34% protected against COVID-19, while those who get both doses are about 89% protected.

“Until you get both shots, you are not well-protected against COVID-19 and its variants,” Lightfoot said. “Vaccination isn’t just a feel-good thing. It’s about protecting you from sickness and death.”

Lightfoot said people in Chicago who have yet to be vaccinated tend to be under the age of 40, and to live in the 60621 and 60633 zip codes on the South and West sides.

“It’s time to get off the fence, to get in, to get yourself vaccinated, but also importantly, stay masked up,” Lightfoot said. “We can’t allow [the delta variant] to spread further or faster than it already has, and it already has an incredible momentum.”

The mayor said the city is trying to do everything it can to refute misinformation being spread about COVID-19 and the vaccines, to convince more people to protect themselves against the virus.

“We have been putting, I think, accurate information out on our websites, through our social media channels, on and on and on, really from the very beginning of the pandemic,” she said. “Yes, there’s a lot of misinformation out there. We’re talking to our electeds and social media companies about being much more aggressive about tagging or taking down information that’s just factually inaccurate.”

As part of the city’s efforts to prevent COVID cases from rising to a dangerous level, Lightfoot said public health workers are going door-to-door in neighborhoods with low vaccination rates to help educate people about the vaccines, and encourage them to get the shot.

The city is also offering vaccinations at home to anyone age 12 and up, for up to 10 people per household, through the appointment-based Protect Chicago initiative. Anyone interested in receiving the vaccine at home in Chicago should call 312-746-4835 or visit chicago.gov/athome.

The mayor and Arwady noted, with Lollapalooza coming up at the end of the month, people who plan to attend should remember they need to be vaccinated or show proof of negative COVID-19 test within no more than 72 hours of the days they plan to attend the festival in Grant Park.

“We want people to have a good time, and we want this to be as safe as it can be,” Arwady said.

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However, despite her concerns about the rise of the delta variant, Arwady said there is no need to implement a mask mandate for Lollapalooza, given that organizers are already requiring guests to show they’ve been fully vaccinated, or have recently tested negative for the virus.

CBS 2 Chicago Staff