Refugees often arrive in Australia without documents, and this usually includes vaccination records.
Doctor Fatin Toma says this is fairly common.
"Some of them, they bring their records, but most of them moved from their original country suddenly, or just without planning, so they don't have their records with them."
Those that do have records are often on different vaccination schedules, which can vary from country to country.
But now it's much easier to get refugees' vaccinations in line with Australia's schedule.
Under the National Immunisation Program, free catch-up vaccines are available to all Australians under 19, and to refugees of any age.
Around half a million young Australians aged between 10 and 19 currently lack full immunisation.
Expert say this threatens what's called 'herd immunity', needed to prevent infectious disease outbreaks.
Public Health Association CEO Michael Moore explains.
"What it means is that for those very small number of people who have compromised immune systems or something, and are not able to be vaccinated, that the rest of the community's vaccination by and large protects them. So it's much less likely statistically that they will get the disease, because nobody else is passing it around."
A generally accepted level is to have 95 per cent of a population immunised to keep it safe.
Earlier this year, a measles outbreak in Romania killed 17 children and infected thousands more -- the result of poverty, and an anti-vaccination movement.
The children who died hadn't been vaccinated.
Dr Toma says any disease outbreak is a dangerous situation.
"There are certain diseases which can circulate in the community and they are very dangerous and they are very serious. They can get so many complications, even death."
New migrants and refugees often aren't aware of the dangers.
The Ewaz family moved to Australia from Iraq in November last year.
They learned about the catch-up service through settlement services, who put them in touch with the Arabic-speaking, Iraq-born Dr Toma.
Their two sons, six-year-old Andre and five-year-old Arman, received their final catch-up injections from Dr Toma.
Alice Ewaz says she is just happy to be settled in Australia.
"I feel happy and I thank God that we reached this safe country. Of course I am happy and it's hard to express how happy I am inside."
Dr Toma says she is always happy to lend a hand, but she does have a soft spot for her fellow Iraqis.
"They are from my home country... I have the same feeling, and I'm happy to help them. I'm very happy to help everyone... but especially from my home country."
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