Tens of thousands of children in Pennsylvania and New Jersey have received their first coronavirus shots, prompting providers to up their orders of doses, bringing school districts into the vaccination effort and ushering in a wave of outreach efforts aimed at kids and parents.

In the first 10 days the two-dose Pfizer vaccine was available to adolescents aged 12 to 15, more than 50,000 in Pennsylvania and nearly 44,000 in New Jersey received first doses. Lines were long at some providers, and school gyms turned into immunization clinics.

But there were also signs that the effort to vaccinate children — seen as key to reaching immunity levels that will suppress the spread of the virus and getting education back to normal — will run up against the same hesitancy barriers and equity divides that have affected the rollout for adults.

» READ MORE: The case for vaccinating teenagers against COVID-19, explained

In wealthy Lower Merion, 900 children were vaccinated last week at a school clinic in three hours, said Marc Ost, co-owner of the pharmacy that ran the clinic, with demand so high they scheduled a second. The enthusiasm among families at the private Friends Select School led leaders to believe they can get a 100% vaccination rate among those eligible, said school nurse Kelly Papianou.

In Delaware County, 1,300 students showed up at clinics serving the school districts of Garnet Valley — where 90% of parents told the district they wanted their 12- to 15-year-olds vaccinated — and Rose Tree Media, said Garnet Valley Superintendent Marc Bertrando.

But a Ridley clinic, which was also open to children in less affluent Interboro and Chester Upland, attracted only 400, said Ridley Superintendent Lee Ann Wentzel. And in Camden, with a public school enrollment that is half Black and half Latino, few parents were calling to ask about getting their kids vaccinated. Families there are “still struggling” with making the decision, said Superintendent Katrina McCombs, and many parents are not yet vaccinated themselves.

“Our population, we know, throughout the pandemic has been hit hardest. We also know that there are trust issues with regard to the history of some things that have occurred in this nation,” said McCombs. ”As much as I can, I talk about my experience [getting vaccinated] so that others who look like me may say, ‘OK, all right, well maybe I’ll give it a try.’”

The opening of the vaccine to adolescents, and the accompanying challenges, has prompted a blitz of town halls, information sessions, parent surveys, and outreach efforts. School districts and providers are hosting clinics, teens are talking up the vaccine to their peers, and school leaders, health officials, and doctors are aiming to answer parents’ questions and dispel worry and myths about the shots.

County health departments, community organizations, and health-care providers like the Children’s Hospital of Philadelphia and the Black Doctors COVID-19 Consortium are all making efforts. But as with the broader rollout, outreach initiatives have been patchwork.

Adolescents can get vaccinated anywhere adults can, provided the clinic uses Pfizer, the only vaccine approved for kids so far. Schools in both states aren’t directly offering or requiring the inoculations, but encouraging them and offering providers space to run clinics.

In Philadelphia, although the School District has been in talks with CHOP about possible clinics, the city is not using the schools as immunization sites.

Doctors and educators say getting children vaccinated is a critical step in suppressing the virus and keeping schools open full-time. The Pennsylvania State Education Association, the statewide teachers’ union that often advocated for a slower, more deliberate reopening during the pandemic to protect its members, last week said the wave of student immunizations will make it possible for a complete return to in-person instruction in the fall.

But state and school officials have been hesitant to set vaccination goals. The Pennsylvania Department of Health only said it is encouraging all those eligible to get their shots, and officials have signaled they won’t mandate them as long as the vaccines remain approved by the federal government only under emergency-use authorization. No state has mandated the coronavirus vaccine for schoolchildren, according to the National Conference of State Legislatures.

“Having [children] receive the vaccine means they won’t serve as a vector to spread it to someone else. That’s just critical,” said Kate Tigue, chair of the state chapter of the American Academy of Pediatricians’ pediatric council. “If you can reach 50, 60% of a given population, that’s going to make a huge difference, particularly in a school.”

Officials and experts have set 70% of the population as an approximate goal for vaccination. Pennsylvania has fully vaccinated half of adults and New Jersey is at 57%, with both states in the top 10 for percentage of population with at least one dose. About 6% or 7% of kids under 18 in each state have gotten at least one shot, based on CDC data and census estimates.

At vaccine clinics, excitement was high last week among adolescents — whose mental health, social lives, and learning were hit hard by the coronavirus pandemic — and their families.

On Wednesday afternoon, emergency-room nurse Jackie Latronica, 38, teared up sitting on Cheltenham High School’s bleachers after her children, Ciara Rodriguez, 15, and Jordan Rodriguez, 15, got their shots.

After watching coronavirus patients suffer and die over the last year, Latronica had been “waiting for the day” her children could get inoculated, she said.

Tigue, the Scranton pediatrician, said she had seen the same kind of relief among patients and parents. Her practice began vaccinating younger teens the day it was approved by the CDC, May 12, and gave doses to 600 or 700 in the first week.

“We’ve had some parents who have been pretty emotional with gratitude,” said Tigue, whose own children got vaccinated. “That’s just an immense feeling when your kids can get protected.”

» READ MORE: Philly schools are planning to reopen full-time, 5 days a week in the fall

Concerns vary, from the same hesitancy that’s kept some adults from getting the shot to child-specific worries. During a virtual information session Tuesday night, parents in the Chester Upland, Interboro, and Ridley school districts typed questions into a chat: How long have the clinical trials in children been researched? Are there potential long-term fertility issues? What about adverse reactions?

CHOP pediatrician Susan Coffin told parents on the call that the vaccine is safe, effective, and has not been shown to disrupt puberty. When side effects occur, they are typically the same short-lived flulike symptoms adults have experienced.

“Every day, we have somewhere between eight and 10 children in our hospital due to coronavirus,” she said. “I really don’t want to have 10 kids each and every day spend part of their summer in our hospital if they don’t have to.”

Many parents who bring their kids to doctor’s visits and have routine questions about the vaccine’s efficacy and side effects “end up saying, ‘Yeah, I want to do this today,’” said Natalie Mathurin, lead pediatrician and associate medical director for Greater Philadelphia Health Action Inc. She’s seen skepticism among her patients, but also reported promising signs since the vaccine was approved, as families start to ask her about vaccination.

» READ MORE: How a year of COVID-19 has challenged and changed one West Philadelphia family

Peer influence is another powerful tool.

As an ambassador for Philly Teen Vaxx, a collective of teens supported by local health-care organizations, the School District, and the city, Makayla Coleman and her peers are working to combat the misinformation she says is rife — efforts she believes are paying off.

“People think they’re using the Black and brown communities as guinea pigs for the virus; people say the vaccine messes with your DNA or makes your hair fall out,” said Coleman, a 10th grader at Carver High School of Engineering and Science in Philadelphia, citing some of the myths she’s heard. “But as time goes on, people have stopped having those fears as much.”

And when parents are hesitant, some teenagers are making the decision themselves. Rudy Fernandez, 48, of Cheltenham is vaccinated, but he had concerns about immunizing his 15-year-old daughter, Gaby. But “she told us” that she wanted to get it, he said, so her parents agreed and she got the shot Wednesday.

As a group of Philly Teen Vaxx ambassadors talked over Zoom on Wednesday, Central High junior Ibthial Gassen said she believed efforts like theirs could save lives.

“This gives us hope in being able to protect ourselves and protect each other,” Gassen, a junior at Central High, said of the ability to get vaccinated. “It brings us back to what was once normal.”

Staff writers Kristen A. Graham and Jason Laughlin contributed to this article.