"It seems to be going well. We are genuinely excited about the results we've seen so far," ABC Online quoted Professor Peter Timms of Queensland University of Technology's Institute of Health and Biomedical Innovation as saying.
The researchers describe chlamydia infection as a major problem that causes a kind of conjunctivitis that can eventually cause koala to become blind.
It can even render female animals sterile in some cases, they say.
"As many as 25 to 50 per cent of koalas coming into care in both Queensland and New South Wales are showing clinical signs of the disease and it seems to be getting worse," Timms says.
"When combined with habitat destruction, chlamydial disease continues to be a major threat to koalas' survival," he says.
The researchers say that their latest study was aimed at determining whether the vaccine could trigger a strong immune response in the animals.
They reported being excited upon finding the shots to stimulate immune system T-cells in the vaccinated koalas.
"A good T-cell immune response is essential if the vaccine is to be effective. It suggests we'll get a good degree of protection in these animals," Timms says.
"If all goes well with this trial our future studies will evaluate the vaccine on sick and injured koalas brought in for care, relocated animals, and koalas in other sanctuaries," he says.
He believes that the findings of their studies may eventually prove helpful in enabling the development of an effective Chlamydia vaccine for humans.
In the long-term, the results of the koala studies could also help in the development of an effective chlamydia vaccine for humans.