Australia has approved and funded a new vaccine designed to protect koalas from chlamydia, a disease that has become a major threat to the endangered marsupial’s survival. The move is part of the country’s broader efforts to restore wild koala populations, which have declined drastically over the past century.
Once numbering in the millions, koalas faced mass slaughter in the early 20th century due to demand for their fur. Although hunting has long been banned, koala populations continue to struggle due to ongoing threats — chief among them, chlamydia.
Chlamydia, a bacterial infection transmitted primarily through mating and sometimes during birth, now accounts for more than half of all wild koala deaths. The disease can cause severe complications including infertility, blindness, and debilitating urinary tract infections. Infected koalas often become too weak to eat or move, leading to a slow and painful death.
After more than a decade of research, microbiologist Professor Peter Timms from the University of the Sunshine Coast has developed a single-dose vaccine tailored specifically for koalas. Timms has witnessed entire colonies edge toward “local extinction” and said infection rates in Queensland and New South Wales are between 50% and 70%.
“This vaccine offers three layers of protection: it reduces infection, prevents progression to clinical disease, and, in some cases, can even reverse symptoms,” Timms said.
Timms collaborated with fellow microbiologist Dr. Samuel Phillips, who helped refine the formula over 15 years. The final version includes three chlamydia protein targets and an adjuvant — all packed into a single shot. The one-dose approach was crucial, Phillips said, because it avoids the need for repeatedly capturing the animals for follow-up treatments.
The team plans to begin distribution with an initial batch of 500 doses early next year, but emphasized the need for additional funding to scale up production. Phillips estimates that wildlife hospitals and conservation programs will eventually require 1,000 to 2,000 doses annually — not including the broader effort to vaccinate wild koala populations.
So far, the Australian government has allocated about $495,000 from a larger $76 million koala conservation fund to support the vaccine rollout. The majority of that budget is currently focused on habitat restoration and national koala population monitoring efforts.
Beyond disease, koalas are also battling widespread habitat destruction, made worse by climate change. In April, hundreds of koalas in a bushfire-ravaged area were euthanized by aerial shooters in an effort to cull the sick and injured. However, the operation left many healthy joeys orphaned, underscoring the complexities of wildlife management in crisis zones.
With the new vaccine offering a real chance to reduce mortality rates by up to 65%, researchers and conservationists remain hopeful that koalas — one of Australia’s most iconic species — may finally begin to recover.