NEW YORK (NewsNation Now) — More major cities are imposing vaccine mandates in the face of the omicron variant. Experts say testing alone isn’t getting the job done because the new variant is so contagious. They want to make sure people are getting their shots.

In New York, proof of vaccination has become the new normal. Now, other jurisdictions are following the city’s lead, developing their own vaccine passports.

“There’s no denying that we are in a fifth wave of COVID-19,” said Chicago Mayor Lori Lightfoot.

In Chicago, indoor vaccination mandates start in the new year, with full vaccination required for anyone 5 and older at most businesses.

“It’s really to protect our hospitals, to protect our population from getting sick (with) severe disease,” said Dr. Monica Gandhi, an infectious disease expert at the University of California, San Francisco.

Gandhi said that, nationally, people are now 20 times more likely to be hospitalized if they’re unvaccinated.

Big cities throughout the country are making already tough mandates even tougher. Beginning next week, New York will begin requiring proof of full vaccination for indoor activities involving anyone older than 12. Similar rules are in place in San Francisco and Los Angeles.

“We have had to make adjustments very, very quickly,” said New York Mayor Bill De Blasio.

Philadelphia’s vaccination mandate for indoor dining starts in the new year.

In Boston, officials announced Monday a vaccine requirement for indoor dining and for all city workers.

“We know that as cases go up, it is necessary to protect everyone who interacts with city government,” said Boston Mayor Michelle Wu.

Boston is working to develop its own app to show proof of vaccination, similar to other cities.

“I think we would be done with all of this if everyone would be vaccinated,” Dr. Robert Velarde, the medical director at Altus Emergency Centers, said on “NewsNation Prime.”

Velarde strongly supports the mandates. He believes we are going back into another surge.

“We are running out of beds,” Velarde said.

Corporate America is also pushing for more people to get vaccinated.

United Airlines has an education campaign for booster shots. Tyson Foods offers them at some production facilities. And Goldman Sachs has been doing that at its onsite health centers for months.

Mask mandates are also returning for some.  

The nation’s capital reinstated its indoor mask mandate Tuesday. The new indoor mask requirement kicked in at 6 a.m. and will continue through the end of January — at which point it will be reconsidered.

There are currently eight states with mask mandates in place regardless of vaccination status. Masks are also required in 16 cities and on all public transit, trains and planes.

NewsNation’s Nick Smith and Tom Palmer contributed to this report.