CHICAGO (CBS)COVID-19 cases in Illinois have surged to the highest daily total in more than a year, and it is putting a serious strain on hospitals.

Health officials fear it is only going to get worse over the holidays. It is also already affecting events in Chicago.

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The excitement for a night at the theatre took a disappointing turn for those with tickets to see “Pretty Woman” at the CIBC Theatre downtown. They arrived to find the show canceled Thursday night due to a small number of breakthrough COVID cases.

“It’s kind of a bummer, but we understand it’s the world we live in now with COVID, so better safe than sorry,” one woman said outside the theatre.

“It’s about safety,” a man added. “We shouldn’t get mad about it.”

The cancellation came as shows in cities like New York have been canceled over the past few days. Variety Magazine reported that on Broadway in New York, a long list of shows have had to call off productions due to COVID cases – including “Mrs. Doubtfire: The Musical,” “MJ The Musical,” “Tina: The Tina Turner Musical, “Harry Potter and the Cursed Child,” “Ain’t Too Proud,” “Freestyle Love Supreme,” and “Hamilton.”

In Chicago, the cancellation of the “Pretty Woman” production coincided with the highest number of reported daily COVID cases in Illinois since Dec. 1, 2020 – 11,858, to be exact.

“The last surge never really ended,” said Dr. Kiran Joshi, senior medical officer at Cook County Health. “It came down to a plateau that none of us were very comfortable with.”

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Joshi said this is a Delta variant surge, and it is taking a toll on Illinois hospitals. Right now, only 9 percent of the state’s ICU beds are available.

And Joshi said new suburban Cook County data show the unvaccinated – not surprisingly – are the most seriously ill.

“We know that unvaccinated individuals are 50 times more likely to be hospitalized with COVID compared to individuals that are vaccinated and boosted,” said Joshi.

Joshi expects there will also be an Omicron variant surge, which could be fueled by holiday gatherings.

His advice is that people who are not vaccinated should not go to holiday gatherings at all.

Otherwise, he said: “I think everyone should consider being tested beforehand, regardless of vaccination status. We’re recommending perhaps two to three days before a holiday gathering, and then on the day of.”

Dr. Joshi and others say masks are more important than ever – whether you are vaccinated or not.

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Meanwhile, will Chicago go the way of New York and require proof of vaccination for indoor spots such as restaurants? Mayor Lori Lightfoot’s administration said it is considering several strategies to try to slow COVID-19 spread.