A single-dose vaccine to protect koalas from chlamydia has been approved for use around Australia for the first time, a move wildlife carers say offers hope for a \u201cheartbreaking\u201d situation.<\/p>\n
Crucially, no booster shot is required, giving researchers hope that the vaccine can eventually be used in the wild. \u201cIt\u2019s difficult to catch a koala once, let alone two or three times,\u201d says Dr Sam Phillips, a microbiologist who has spent almost a decade working on the vaccine.<\/p>\n
Phillips says about 50% of koalas have chlamydia, although rates in some wild colonies may be as high as 70%. Combined with deforestation and traffic accidents, the other major threats to the species, he says the disease is \u201ca huge, devastating issue\u201d.<\/p>\n
What is changing with the approval of this koala chlamydia vaccine?<\/p>\n
After extensive clinical trials treating hundreds of koalas, the veterinary medicines regulator recently gave the go-ahead for wider use nationally, in hospitals, veterinary clinics and in the field.<\/p>\n
A spokesperson for the Australian Pesticides and Veterinary Medicines Authority said the vaccine was approved under a minor use permit,which allows registered vets, or people under their direction, to use it.<\/p>\n
Which koalas get the jab?<\/p>\n
The first batch of the vaccine, expected to be about 500 doses, will be ready to roll out from early 2026. The university\u2019s team wants funding to scale up production to ensure the vaccine can be provided free to more providers.<\/p>\n
The plan is not to vaccinate every koala in the national population, which the CSIRO estimates at between 224,000 and 524,000. There aren\u2019t enough doses.<\/p>\n
\u201cThis would be a vaccine program specific to koalas that are at risk,\u201d Phillips says.<\/p>\n
Phillips says the current focus is vaccinating koalas in wildlife hospitals who are already under general anaesthesia for health checks. The hope is to expand efforts to wild populations, but vaccinating wild koalas, including healthy ones, will take time, resources \u2013 and highly skilled koala catchers.<\/p>\n
\u201cKoalas obviously live high up in trees, they\u2019re not necessarily easy to catch to vaccinate,\u201d Phillips said. Even bringing in koalas found on the ground, which are likely to be already sick or injured, has its challenges. \u201cThey\u2019re wild and they\u2019re scared. As far as they\u2019re concerned we\u2019re predators,\u201d says Vickii Lett, koala species coordinator with wildlife rescue organisation Wires.<\/p>\n
\u201cIf you get a koala that\u2019s really cooperative and doesn\u2019t argue with you when you\u2019re trying to catch it, then you know they\u2019re in real strife,\u201d she said.<\/p>\n
How does the vaccine affect the koalas?<\/p>\n
The vaccine covers three different variants of chlamydia and uses a unique \u201ctriple adjuvant\u201d, an ingredient used to improve the immune response.<\/p>\n
The drug, developed by researchers from the University of the Sunshine Coast in partnership with Australian animal health company Tr\u00e9idlia Biovet, can be given as a single dose, delivered by needle from a qualified vet.<\/p>\n
Koalas do not have to be anaesthetised to be vaccinated. Side effects are minor and include swelling around the injection site for a day or two.<\/p>\n
The vaccine rollout to at-risk koala populations would ideally occur alongside other measures tackling threats such as deforestation, predatory animals and car accidents, Dr Sam Phillips says. Photograph: University of the Sunshine Coast<\/p>\n
Until now, antibiotics have been the only treatment available outside clinical trials, and have to be specially made up. These can also have serious and sometimes deadly side effects. They can kill the koala\u2019s microbiome, which can be fatal if not carefully managed, Lett says. In addition, after antibiotic treatment, once animals recover and are released back to the wild, they can be reinfected.<\/p>\n
According to Phillips, research has found the vaccine reduces likelihood of koalas developing symptoms of chlamydia during breeding age, and lowers mortality rates in wild populations \u201cby at least 65%\u201d.<\/p>\n
Why are koalas so badly impacted by chlamydia?<\/p>\n
It\u2019s unclear how and when koalas first caught the highly contagious disease. Various theories include the possibility it was introduced through infected livestock after European settlement, Phillips says.<\/p>\n
Wildlife veterinarian Dr Leanne Wicker says the sexually transmitted disease, which affects both males and females, can be \u201creally nasty\u201d. \u201cInfected koalas can become blind and infertile.\u201d<\/p>\n
She says the vaccine\u2019s approval is good news for northern populations especially.<\/p>\n
\u201cThey\u2019re already suffering significantly from habitat loss, bushfires and the impacts of climate change \u2013 we know that their population is dwindling. Chlamydial disease is an additional stress that the population just doesn\u2019t need.\u201d<\/p>\n