What is a vaccine passport and how would it be used?

CHICAGO (WLS) -- As Chicago opens the COVID vaccine to more people Monday, the federal government is working behind the scenes on a "vaccine passport."

"The vaccine passport is the idea you have a document that states you have been vaccinated against COVID-19 and it would allow you access to what used to be normal life," said Craig Klugman, a professor at DePaul University College of Science & Health

Having a vaccine passport could be used to give you access to sports and entertainment venues, restaurants, travel -- just to name a few.

The state of New York already launched the nation's first vaccine passport last Friday.

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It works by showing a barcode on your phone or a printout to prove you've been vaccinated.

While there are 17 apps being developed in the United States, Klugman said there should be a universal one used worldwide.

"If the World Health Organization came out with an app that would be recognized all over the world, that would make it easier for all of us," he said.

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However, Chicago is far from launching its own vaccine passport, with Mayor Lori Lightfoot voices some of her concerns.

"Obviously, there's a lot of privacy issues that have to be addressed before that becomes a certainty," the mayor said. "I don't think we are close to that now, but that's been a discussion for some time."

There are also equity concerns since vaccine access in low-income minority neighborhoods has been an issue, as well as access to public spaces. Despite that, some public health experts said that should not stop the vaccine passport idea from moving ahead.

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"You should not let that derail what is a very promising approach to successfully promoting vaccine, reopening society and increasing freedom for many Americans," said Dr. Ronald Hershow with UIC School of Public Health.

Experts said a vaccine passport should not be put into use until there is enough vaccine to vaccinate everyone who wants one.

In Illinois, just over 16% of the population is fully vaccinated.