For the first time, a wild koala has been fitted with a biodegradable implant that collapses a two-dose chlamydia vaccine into a single capture, clearing the biggest practical barrier to protecting the endangered marsupial at scale. That is according to the Queensland University of Technology, whose researchers sedated an 18-month-old female named Bamse at Currumbin Wildlife Hospital on the Gold Coast, injected the first dose, set the implant, and returned her to bushland the same day.
The implant is designed to break down after 30 days and release the second dose on its own, eliminating the follow-up capture that has slowed large-scale vaccination, made it costly, and made it stressful for the animals. Bamse now wears a GPS collar and will be tracked for at least six months, one of five wild koalas from Burleigh already carrying the device.
“It’s absolutely critical the vaccine is rolled out en masse to at-risk populations,” said Michael Pyne, the senior veterinarian at Currumbin Wildlife Hospital who fitted the implant and has worked on koala chlamydia vaccines for more than five years. Both Bamse and a second recaptured koala tested chlamydia-free at their one-month check, an early sign the implant matches the two-injection course it replaces.
More than 500 koalas have already been vaccinated at Currumbin and the Moggill Koala Rehabilitation Centre, including over 30 young animals from Elanora on the Gold Coast, where the two-shot programme stabilised a collapsing population. Admissions from that area have fallen 75 per cent since 2020, when more than 70 per cent of Elanora koalas reaching the hospital carried the infection, and 41 joeys and 13 grand-joeys have since been born.
Chlamydia ranks among the leading forces behind the decline that saw koalas listed as endangered across Queensland, New South Wales, and the Australian Capital Territory in 2022, the three jurisdictions the National Koala Monitoring Program counts as its listed population. Its most recent data-driven estimate put that listed population at between 95,000 and 238,000, narrowing to between 86,000 and 176,000 once adjusted for survey gaps, even as a separate New South Wales survey counted 274,000 koalas in that state’s forests alone.
An independent report prepared for the Queensland Government backed the vaccine, finding it produced “substantial reductions in chlamydial disease and mortality” in vaccinated wild koalas and judging it feasible to deploy at scale. The research, by Lyndal Hulse of The University of Queensland, took swabs from more than 1,100 koalas at wildlife hospitals across the state’s south-east.
“It’s showing that the two-shot vaccine from QUT is actually working,” Hulse said of the falling infection burden recorded at Currumbin. She has recommended prioritising the Somerset-South Burnett, Redland City, and Moreton Bay council areas, where the disease load runs highest.
“What makes this implant so exciting is its versatility,” said Freya Russell, the QUT biomedical scientist who assisted the procedure, adding that it could carry other multi-dose animal vaccines and medicines. Russell said the team is in talks with livestock groups, with cattle farmers among those drawn to the one-capture approach.
“We need to tackle chlamydia and restore and protect their habitats,” said Tanya Pritchard, senior manager of koala recovery at World Wide Fund for Nature Australia, which is funding the trial with the furniture brand Koala. Pritchard called Bamse a trailblazer whose treatment could rank among the most important moments in a century of koala conservation.
Hulse has urged the state to prioritise its worst-hit council areas, after swabs from Logan City koalas found 58 per cent carrying conjunctival chlamydia and 56 per cent the urogenital strain, the heaviest disease load recorded in the south-east.
