Health officials say the COVID surge is fueled by unvaccinated Americans and the highly contagious Delta variant.
The musical festival typically draws about 100,000 attendees per day, and that has some people worried.
"I do think there is going to be a significant risk of transmission at a tightly packed event such as Lolla, unfortunately," Dr. Zachary Rubin said.
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Lollapalooza said they are enforcing health measures at the direct of the city and the Chicago Department of Public Health.
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Each person will have to show a printed vaccine card at the gate, or proof of a negative COVID-19 test taken within 72 hours of attending. Since the festival is four days long, weekend-long attendees will have to get tested multiple times.
If you don't have the papers, you will not get in.
"We have tightened up the security procedures," said Bob Klich of Monterrey Security.
A retired CPD commander with more than 35 years of law enforcement experience, he knows how to run a festival. But this year their biggest concern is health.
"It is going to be a challenging thing to do, but this is a new world that we are entering as America and the world starts to open up," Klich said.
Klich and other security team members will be keeping a close eye out for fake vaccine cards and anyone trying to sneak in.
"There are two types of fences. The main fences are very hard to get over. They are going to be patrolled by our security and security from other companies, along with CPD," he said.
But a rise in cases is still expected by many doctors.
Dr. Robert Citronberg with Advocate Lutheran General Hospital weighed in on the risks.
"The good news is it's an outdoor event and we know that transmission of the virus is much less likely is much less likely in outdoor spaces," Dr. Citronberg said.
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While some health experts say it's unlikely to become a super spreader event, they say there are chances for a spike in COVID cases. And Dr. Citronberg issued a warning for those who aren't vaccinated.
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"Every single person at that event who is unvaccinated is at risk of getting COVID-19," he said. And I think you should really give consideration about not going if you are unvaccinated.
Dr. Citronberg said if you are unvaccinated and you do go, regular cloth masks won't do. He said to wear an n-95 type mask for maximum protection.
Lollapalooza gets underway Thursday and runs through Sunday.
Lolla's website has listed the safety protocols now in place. You must be fully vaccinated, or have a negative COVID-19 test within 72 hours of attending Lolla. When you enter, you must have a printed copy of your vaccine card, vaccine record, or negative COVID test. You must also have your festival wristband. If you're unvaccinated, Lolla's website says you have to wear a mask as well.
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