The Best Birthday Present in 2021? A Covid Vaccine.

Zoe Tu, a seventh grader in Brooklyn, likes to celebrate her birthday with dulce de leche Haagen-Dazs ice cream cake. This year, her 12th, was no exception, but the day was also marked by a treat of another kind: her Covid vaccine.

Zoe got the shot the first day she became eligible, on Aug. 2, and it was accompanied by a $100 gift certificate given as a vaccine incentive at the Barclays Center. (Her mother allowed her to spend it on anything she wanted.)

“The nurse was really excited about wishing me a happy birthday,” Zoe recalled.

Zoe’s mother, Nicole Tu, said she had told her daughter she could wait if she wanted. But, Zoe said: “I knew that was the quickest I could get it. I was excited because I could feel safer.”

Many birthdays are rites of passage, especially for young people. Getting to 14 or 15 opens the doors to high school; turning 17 grants permission to view R-rated movies; 18 delivers the right to vote; and 21 brings the legal age to buy alcohol in many states.

But since early May, 12th birthdays have new significance, because the Food and Drug Administration gave the Pfizer-BioNTech Covid vaccine emergency use authorization for children 12 and older.

At least 52 percent of children ages 12 through 17 in the United States have received at least one dose of a vaccine, and about 40 percent are fully vaccinated, according to early September data from the Centers for Disease Control and Prevention. Scientists say a decision on whether children younger than 12 can get the shots could still be months away.

At least one school district, in Culver City, Calif., has announced that it will require eligible students to get a Covid vaccine, and more mandates could be issued as the Delta variant fuels significant increases in cases among young people. A recent poll by The Associated Press-NORC Center for Public Affairs Research found that 55 percent of Americans supported vaccination requirements for eligible students.

Dr. Anthony Fauci, the nation’s leading infectious-disease expert, has said he supports such mandates for school children.

But parents are now navigating a tricky moment in which some children are vaccinated while many others, who are under 12, are not. Some parents, including Ms. Tu, are for the most part limiting their children to indoor play dates with vaccinated friends.

After Zoe got the shot, her mother posted on Instagram to mark the moment: “Turning 12 in 2021 means a different kind of celebration,” Ms. Tu wrote, with syringe and birthday cake emojis.

Zoe’s vaccination was a milestone moment for her parents, too. “On her birthday we’re one step closer to being safer because our whole family can be vaccinated,” Ms. Tu added. “It’s a new chapter for us.”

For some young people, getting vaccinated adds poignancy to a birthday. Many spent the past year isolated from friends, yearning for normalcy and confining their friendships primarily to phones and computers.

Several studies have shown deteriorating mental health, including bouts of anxiety and depression, among teenagers during the pandemic. Getting a Covid vaccine offers some teenagers a glimmer of promise for more socializing.

Some students did not want needles to mar their actual birthdays. Sebastian Holst, 12, of Brooklyn, was relieved that his parents had scheduled his vaccine appointment for several days after his birthday in May. That way, he was able to hold a Zoom birthday party with friends, take a walk with his mom and enjoy his dad’s tacos, free of worry about any possible side effects.

“Getting vaccines doesn’t feel great, but I know I have to, so I suck it up,” he said.

Heading to the Javits Center in Manhattan later that week for his shot brought a burst of excitement as he envisioned a new school year that might improve over last year’s. Sebastian’s school offered a blend of in-person and remote learning last year, and on the days when he was remote, he missed bumping into friends in the hallways. And remote classes via Zoom eliminated the separation between home and school, he said.

Sebastian said he had been one of the first among his friends to get a vaccine, and relief overtook his anxiety when it was over. He texted friends to help ease their worries.

“I knew it was better to get a little pointy needle than Covid,” he said.

There’s also fanfare, for many, in the actual experience. Some young people received their Covid vaccines at sites that held emotional meaning, and others happily welcomed the free items given as incentives to get the shot.

To Zoe, the items given out at the Barclays Center vaccination site amounted to more presents: She got a Nets T-shirt, an “I got the shot” sticker and a gift card, which she spent on clothing from the Gap and Brandy Melville for the new school year.

Myles Knollmueller, who turned 12 in July, got the vaccine at the Brooklyn Children’s Museum shortly after his birthday. He found it jarring to visit a space he loved, complete with its water play area, transformed into a medical site.

“It was very weird, because that was a place I went to so much when I was younger to have fun and be with people, and now I was going to get a vaccination for a global pandemic,” Myles said.

Myles spent part of the summer at camp in Great Barrington, Mass., where some of his friends had already been vaccinated. When he turned 12, and celebrated with cake for breakfast, his friends cheered the fact that he would soon be able to get his shot, too.

As he watched the nurse prepare a syringe, Myles felt nervous about the needle jab but excitedly rolled up his sleeve. “There was a kind of achy feeling in my stomach, but it went away,” he said. “Then they were like, ‘Wow nice job, you’re halfway vaccinated.’”