Albury Wodonga Health director of paediatrics Dr Mark Norden, based in the NSW-Victorian border region, said the trial was "ground-breaking" and would help prevent future hospitalisations.

OM-85 is a tasteless capsule that gets broken into a drink.

The medication contains protein that kills bacteria and stimulates the immune system.

At present, there is no medication that prevents children in that age group from being hospitalised when presenting with the condition.

"The reason we need to do this is because a viral-induced wheeze looks like asthma," Dr Norden said.

"It responds to Ventolin to a degree, but it doesn't respond to the other (puffers) that asthma responds to."

Madelyn Schindler, 3, of East Albury, has been part of the study for three months.

She takes the capsule for the first 10 days of the month, once a day in the morning. She also uses Ventolin as needed.

Her mother Lyndell said so far the family had seen a steady improvement in her daughter's condition.

"She was getting admitted into hospital every four weeks (before the trial)," Mrs Schindler said. "She's an absolute trooper."

Madelyn's parents realised the wheeze was a problem when it "kept on getting progressively worse" and she "had to spend three good solid days in hospital".

"She's had a wheeze since she was about two," Mrs Schindler said.

"We've had quite a few hospital admissions."

Dr Norden said he hoped preschoolers could better fight viruses and not end up with the virus-induced wheeze that "gets them into hospital repeatedly".

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While taking part in the trial, Madelyn has not been admitted to the hospital since August. She attends day care three times a week.

"It's all of the viruses at day care where she'll get a small cold and that will flare up her wheeze really bad," Mrs Schindler said.

The multi-centre study at more than 30 hospitals across Australia and New Zealand aims to recruit 2200 children.

Half the children will have the OM-85 capsule and the other half a placebo.

Albury Wodonga Health clinical nurse educator Danielle Hanlon said because it was a double-blind trial, "nobody would know until the end" which capsule was taken.

The trial currently has six participants from Albury-Wodonga.

Interested families can contact the children's ward at Albury hospital or visit the Circan ARROW Trial website, circan.org/om-85/.