Get ready to start proving you're vaccinated if you want to dine inside

• Restaurants across the nation are beginning to require proof of vaccination to dine indoors.
• Restaurateur Danny Meyer told CNBC he feels a "strong responsibility" care for employees and guests.
• The new policies come amid a surge in COVID cases nationally and lagging vaccination rates.

If you want to keep dining indoors at restaurants, get ready to prove you've been vaccinated.

With the Delta variant continuing to spread throughout many parts of the US and the Centers for Disease Control and Prevention updating its mask guidelines this week, businesses, universities, and government agencies across the country have begun updating their vaccine policies.

For some institutions, vaccines will now be mandated for employees - for others, the customers they serve.

In New York City, the site of a catastrophic wave of infections last spring and where cases and hospitalizations have recently risen, this shift has already begun.

Union Square Hospitality Group, which owns Gramercy Tavern, Manhatta, and Union Square Cafe, will now require patrons to show proof of their vaccination status upon arrival if they want to dine or drink indoors. The group will accept a physical vaccine card or a photo of one; New York State's vaccine passport, Excelsior Pass; or other state vaccine passes.

Danny Meyer, the famed restaurateur and the group's CEO, told CNBC on Thursday that the decision is the "most logical thing I've ever seen."

"I'm not a scientist, but I know how to read data and what I see is that this is a crisis of people who have not been vaccinated, and I feel strong responsibility, on our part as business leaders, to take care of our team and our guests, and that's what we're doing," he said.

Meyer also founded fast food chain Shake Shack, and he told CNBC the chain would make its own decision about vaccines.

Read more: Vaccine mandates are coming, and it's about time

Hart's, an intimate Brooklyn-based restaurant beloved by critics, recently announced that it would reopen after 15 months - but with the stipulation that guests would need to be vaccinated to dine indoors.

"Our indoor dining space is available for fully vaccinated guests only. Please bring proof of vaccination when you come," the restaurant's website reads. "If you haven't yet been vaccinated, we're still excited to see you, and we welcome you to join us outdoors."

Establishments in other regions are enacting new policies as well. The SF Bar Owner Alliance, a group of 500 bars in San Francisco, announced this week that it will require customers to show proof of vaccination or a negative COVID test. The group said that it's "extremely concerned by a recent uptick in cases of COVID-19 among our staff members, especially those who are fully vaccinated."

A group of New Orleans music venues has enacted a similar policy in an effort to curb the rise in COVID cases locally.

These changes come amid lagging vaccination rates and surging cases in many parts of the US. Nationally, the number of Americans who are fully vaccinated hovers just under 50%, according to CDC data, and states like Louisiana are seeing an "exponential surge" in hospitalizations due to COVID, a doctor from the state recently told CNN.

While it's still possible for vaccinated people to contract the virus, the vaccine protects against more serious cases, Christopher Murray, the director of the Institute for Health Metrics and Evaluation, recently told Insider's Hilary Brueck.

"The vaccines, especially for the Delta variant, are better at preventing severe disease and death than they are at preventing infections," he said.