There are twenty million people worldwide suffering from Type 1 diabetes, for which there is currently no cure - only ways to manage the symptoms.

Katie Goodhart is nine-years-old. Not one day since she was one has this little girl been able to drop her guard against a disease that can kill her in her sleep - Type 1 diabetes.

Mum Erin is on watch around the clock. “The worst case scenario is that this costs her a life,” Erin said.

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Her answer could come from Professor Len Harrison.

“I've been working on Type 1 diabetes prevention for about 30 years, and so this in a way is a culmination of all that basic research and animal research. If we were able to prevent Type 1 diabetes, I think I could eventually retire, but I have no intention of retiring until we get close to that at least,” Professor Harrison said.

Twenty million sufferers worldwide are praying Professor Harrison doesn't give up and that he finds a miracle. And their prayers have almost been answered.

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Type 1 diabetes differs dramatically from Type 2, which is usually triggered by unhealthy lifestyle habits.

People are born with Type 1, it's in their DNA. Sufferers can be fit and healthy, and they are often young children when diagnosed with a condition of which they'll never grow out.

“We're hoping it will be the holy grail of Type 1 diabetes - a simple bottle, a spray, in which insulin is used to trick the body into making an effective response,” Professor Harrison explained of his discovery.

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It works through a squirt up the nostril which sends vaccine droplets to the back of the nasal passages. This then releases special regulatory cells which head off like soldiers, attacking the killer T cells that block production of insulin in the pancreas and cause Type 1 diabetes.

It's simple and the cure is close to being on chemist shelves - some believe it’s just two years away. But first this scientist needs thousands of people to help - from children as young as four, to adults up to 30 years old, all without Type 1 diabetes but with a relative who has it. And time is of the essence.

“It's a horrible thing but it would be a great thing to stop,” Professor Harrison said.

Simon Frost has Type 1 diabetes and manages his blood sugar levels with an artificial pancreas pump. He still remembers the day he diagnosed, when he was twelve-years-old.

“It was devastating obviously, and I've lived with that for the last 25 years of my life,” Frost said.

Frost has registered his two sons in Professor Harrison's vaccine trial. “If there was something that could prevent them from developing diabetes, that would be one in a million,” he said.

“Six Australians are diagnosed with diabetes every day and if one of my boys were diagnosed with diabetes we'd be devastated. It's really important that people do this, participate in this trial and help to find a possible cure. It's a chronic disease, it's debilitating.”

Susan Alberti is a mum who aches inside every day after her daughter died of a heart attack as she sat beside her on a plane. Danielle was diagnosed with Type 1 diabetes when she turned twelve, and her heart attack was one of the many complications that come with this relentless disease.

“Here we have this perfectly healthy young woman, good at everything that she undertook, and all of a sudden she was diagnosed with Type 1 and it impacted her whole life. She was facing thereafter complications which unfortunately she suffered along the way, and after twenty years she was diagnosed with severe complications,” Susan said.

Susan doesn't want another mother to feel her pain, and has since dedicated her time to help fundraise for research.

“If we can find a vaccine for Type 1 diabetes we're certainly well on the way to finding a cure for the disease,” she added.

So the world's eyes are on the quietly spoken man who is taking on a killer.

“This trial is aimed at identifying children with pre-clinical diabetes, treating them with a nasal insulin vaccine, and stopping the progression of the disease so they never present with the disease at all,” Professor Harrison explained.

And for Erin, it can't come fast enough. Her brother David died of the disease when he was 27 - at home, in a coma on his own.

She knows what it means for little Katie to live with Type 1 diabetes every day.

“The feelings and the emotions that go along with it and the frustrations - when you get tired and you go ‘I just want a day off’ and there is no day off, there's no night off. It just goes on and on and on,” she said.

“It’s hope. It's the real hope of a cure and it's that inspiration to keep going,” Erin concluded.

• Stop Diabetes Australia - www.stopdiabetes.com.au