A Melbourne boy is battling a disease so rare that it's thought he is the only person in the world with it.

It means frequent doctors visits, missed school and daily worry.

Aydyn Stewart, 4, is used to

needles, IVs, doctors, nurses and hospitals. Wearing a surgical mask in public is normal.

"Because we don't want to get sick by people," Aydyn said.

It's hard to believe this is the norm for such a young boy.

"We are dealing with a real life bubble boy," said his mother, Andrea Cannizzaro. "Imagine if you woke up today and you're ready to face the world, and you're up and out. And within three hours you have a 106-degree fever and you can't even move."

Aydyn was diagnosed with Common Variable Immunodeficiency (CVI) in October after a lifetime of poking and prodding.

The CVI combined with other factors make his specific condition so rare it affects one in 6 billion people. In other words, he is thought to be the only person in the world suffering from it.

Simply put, his plasma cells aren't capable of producing antibodies to fight infection.

His mom describes it as trying to build a house without having a foundation. 

"There are treatments available, but they may not work for him or 'stick' traditionally as someone who already has their foundation, or their walls, or their bricks," Cannizzaro said.

It's a new normal for this family. They have to be careful around crowds, taking extra precautions on Disney trips and sporting events.

Aydyn has missed more than 60 days of school this year being sick or in the hospital.

But for his mom, not knowing how to treat her son's disease is the hardest part. They've seen several specialists, but she's still hoping someone in the medical field can take on his case to find a way. 

"The grim reality is, if I can't help you, at least I can pass it along to someone who may be able to help you," Cannizzaro said of the specialists they've seen so far.

Aydyn's family is holding a fundraising event for his treatment. It takes place from 4 to 8 p.m. June 3 at the Jersey Mike's located at 90 Hibiscus Blvd. in Melbourne.