New York City yesterday became the first city in the U.S. to require proof of coronavirus vaccination for indoor dining and other leisure activities, a measure popular among public health experts but previously squashed by political backlash to "vaccine passports."

Why it matters: Employers and now local governments are starting to ensure that remaining unvaccinated will have consequences for everyday life, testing the resolve of those who say nothing could persuade them to get a shot.

Driving the news: New Yorkers soon must be fully vaccinated to dine indoors, visit gyms or participate in other indoor entertainment.

• Some restaurants and bars have voluntarily adopted such policies already, but New York has become the first government to mandate them.
• Denver recently announced that it will require city employees and private-sector workers in "high-risk settings" to be vaccinated, and New Jersey is also requiring some of the state's frontline workers to be vaccinated.
• Employer vaccine mandates have continued to spread like wildfire. Tyson Foods notably announced yesterday that it will require its workers to be vaccinated, even though around half of them currently are not, per the NYT.

The big picture: Several cities and states have recently brought back mask mandates following the CDC's recommendation that vaccinated people resume indoor mask-wearing in hotspots.

• New evidence suggests that vaccinated people can catch and transmit the virus, but the vast majority of the problem is among the unvaccinated —prompting complaints about vaccinated people being punished for the choices of the unvaccinated.
• Some experts say that the lack of a vaccine verification system meant that the CDC's decision to lift masking recommendations for the vaccinated was premature, as unvaccinated people would probably remove their masks as well.

Vaccine passports may be more effective than mask mandates.

• "The truth is that nothing we’ve done except vaccines has worked," said Georgetown Law professor Lawrence Gostin. "Vaccine mandates and a vaccine passport will absolutely get us back to normal."

Between the lines: Dropping the push for an easy digital vaccine verification system may look like a bad idea in retrospect, too.

• For now, most Americans' only proof of vaccination, should they need it, is their paper CDC card.

Yes, but: Employer vaccine mandates and vaccine passports, if they catch on, will eventually run into a red wall.

• Many GOP-led states preemptively put limitations on vaccine requirements for employees or the use of vaccine passports.
• It's unclear whether any other governments will take the New York City approach. President Biden said yesterday that he supports businesses that require vaccine verification, and that he thinks other cities should follow New York's lead.

What they're saying: "People are going to get a really clear message: if you want to participate in our society fully, you've got to get vaccinated. It's time," NYC Mayor Bill de Blasio said at a press conference.

• He added that a blanket mask mandate could remove an incentive to get vaccinated, per the NYT.

What we're watching: There are hints that restrictions on the unvaccinated could increase once the vaccines are fully approved by the FDA.

• “It’s very difficult for us to come in and mandate a vaccine that isn’t even federally approved yet, the authorization hasn’t been final yet, so stay tuned,” Delta Air Lines CEO Ed Bastian told CNBC yesterday.