MIAMI (AP) — When Oliver Burkhardt underwent leukemia treatment at age 9, he'd enter the hospital wearing his patch-covered denim jacket. Pokemon. Superman. NASA. Police, fire, military. Classic rock bands. About 50 patches sewn on by his parents, selected from thousands sent by well-wishers worldwide after his dad made a social media request.

The jacket became Oliver's suit of armor, deflecting his disease — and the nasty side effects of his treatment. It sparked conversations with nurses. His parents decorated their own jackets, showing they are a team. The patches made Oliver feel special.

“I knew people were looking out for me, they gave me positive vibes, that people loved me,” said Oliver, now 13 and in remission.

Seeing how the jacket and its patches helped Oliver, he and his parents, Brian Burkhardt and Trisha Brookbank, thought other kids battling cancer might like one, too. The couple, who come from art backgrounds, reached out to their designer friends and within a day received 300 renderings for possible patches.

The Oliver Patch Project was born.

Three years after launching, the charity has provided more than 1,600 children from infancy to 19 years with either a free denim jacket or tote bag. They are adorned with 20 patches selected by the child or parents from the program's website, then each month they receive another patch in the mail.

On a recent afternoon at the charity’s office west of Miami, a dozen boxes containing a jacket or tote awaited pickup, heading to homes in such cities as Corpus Christi, Texas; Eagle Mountain, Utah; and Murietta, California. Children with cancer from all 50 states have joined.

“This program is 100% about empowering the kids and making them feel like they belong to a much bigger community, that they are not alone,” said Brian, a former creative director who now runs the charity full-time. “It’s not really about the patch, it's about belonging.”

Parents also receive a box of 13 milestone patches to gift their child while they're undergoing a common cancer treatment or experiencing a side effect. A gorilla for starting chemo. A bald eagle for hair loss. A polar bear for fever. They help alleviate some of the trauma as the child works toward the “I Rang the Bell” patch for completing a round of treatment.

So they don't feel neglected, siblings also get special patches — something Oliver's parents realized was important from his younger brother, Peter.

“Everything kind of shifts all your attention to being on the child who’s sick,” said their mom, the chief financial officer at her family's interior design firm.

The cancer program is limited to the United States, but the charity recently received funding to send patches to sick children participating in experimental drug trials in the U.S. and 18 other countries.

The charity's roots began in 2020 shortly after Oliver was diagnosed. He struggled with chemotherapy, and his dad wanted to find something that would bolster his spirits and show he had support.

“He was very tired and very not feeling well,” Brian said.

One day, he noticed patches he'd tossed into his desk drawer. Oliver might like getting some in the mail, he thought, and the family's friends could still do it during the COVID-19 lockdown.

“It’s an easy ask. They can drop a patch in an envelope and, in return, it gave Oliver something to look forward to. Checking the mail every day would get him off the sofa,” Brian said.

He posted his request on Facebook. Friends shared it.

The first patch soon arrived: a kangaroo. A trickle became a torrent — 2,000 arrived that month, 70% from strangers.

“I was like, ‘Wow, this is all for me?' I was like genuinely super surprised,” Oliver said. “They were all different colors and they all had nice notes, like ‘Hope you feel better.’” His parents sewed some onto the family's jackets while sitting in his hospital room.

After getting the idea for supporting other children, Brian enlisted help. Men's clothier Perry Ellis donates jackets and tote bags. Foundations and donors provide funding. The charity hired a patch manufacturer and a seamstress. The charity spends about $350 per child.

As the Oliver Patch Project grew, word spread to children’s hospitals, parental support groups and Ronald McDonald Houses, where families sometimes live during treatment. About 30 children a week now enroll.

Dr. Maggie Fader, an oncologist at Miami's Nicklaus Children’s Hospital, where Oliver was treated, said boosting a sick child’s morale makes recovery easier.

“If patients start to become depressed or negative about the way things are going, they also start to be less cooperative,” Fader said. “We can give them medications. We can administer IV fluids, we can give them chemotherapy, but we can’t make them eat. We can’t make them have good nutrition. We can’t make them comply with all their oral medications when they’re home. Those are things where they have to be willing and participating.”

Ellora Hendrickson, a 7-year-old from North Smithfield, Rhode Island, decorated her jacket with such patches as a ballerina because she takes dance lessons, and an avocado, a favorite food. Diagnosed with kidney cancer last year, she underwent surgery, radiation and chemo before receiving her bell ringer patch in February.

“The patches are really special to me because they helped my journey through cancer,” she said.

Her mom, Ashley Hendrickson, learned of the program through social media from another parent whose child has cancer.

“It was really nice to be able to have something fun to associate with these kind of otherwise fairly scary milestones,” said Hendrickson, a pharmacist. “The dichotomy of something so heavy being associated with something as joyful and very childlike as the patches is not lost on me.”

Becky McHardy of Norwalk, Connecticut, said though her daughter Millie is only 3, she enjoys playing with her patches. Millie is recovering from an abdominal tumor — she's had surgery and is seven months into a 10-month chemotherapy regimen.

“Every time she does something that’s hard, whether it's chemo, a transfusion or whatever it is, she gets a new patch. I sew those onto her jacket and she loves that," McHardy said.

Oliver said knowing that a project born from his illness helps other children “is amazing.” He sometimes travels to meet project recipients, like at a recent event hosted by the Nasdaq Stock Market in New York City. The exchange posted the kids' picture on its Times Square video board.

“It makes me feel great that I’m able to talk to other kids like me, share what this is all about and hopefully help more,” he said.