Want to Party? You Might Need a ‘Vaccine Passport.’

At some parties and night clubs, C.D.C. vaccination cards are the new velvet rope.

You could hear the music from the sidewalk, high-spirited renditions of “Ice Ice Baby” and “MMMBop.” It was ’90s night at Rumi, a ballroom and event space in the Chelsea section of Manhattan, and millennials and Gen Zers lined up to get inside. They dressed the part in tracksuits, neon crop tops, denim overalls and scrunchies. To enter, they had to pass two checkpoints. First, a bouncer verified IDs and took temperatures. Then, Joseph Ko, one of the ballroom’s owners, confirmed that each person had been fully vaccinated for Covid-19. The process took about five minutes.