Starting Jan. 3, people in Chicago will have to show proof of vaccination against COVID-19 to enter certain indoor spaces.

Proof of vaccination will be required at restaurants, fitness centers and indoor entertainment venues, the city's health department said Tuesday. The mandate applies to anyone 5 years and older.

Starting January 3rd, the City of Chicago will require patrons of certain indoor spaces to be vaccinated against COVID-19.

This decision is driven in part by the Omicron variant and is in line with requirements already in place in other big cities including NYC and LA.

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— Chicago Department of Public Health - CDPH (@ChiPublicHealth) December 21, 2021

The decision comes as the omicron variant spreads rapidly across the U.S.

President Joe Biden addressed the nation about the variant Tuesday. He said people who have been vaccinated and boosted should have sufficient protection from omicron.

"If you're not fully vaccinated, you have good reason to be concerned," Biden said. "You're at a high risk of getting sick."

Chicago's announcement comes one day after the mayor of Boston said vaccines would be required to enter indoor settings.

New York City and Los Angeles have similar vaccine mandates.