The University of the Sunshine Coast has achieved a world-first breakthrough with the regulatory approval of a single-dose vaccine designed to protect Australia's endangered koalas from chlamydia infection. The vaccine, approved by Australia's Pesticides and Veterinary Medicines Authority, represents over a decade of research aimed at combating one of the greatest threats to koala survival.
Critical Disease Burden in Wild Populations
Chlamydia infection has reached devastating proportions among Australia's koala populations, with some individual wild colonies experiencing infection rates as high as 70%. The disease causes painful urinary tract infections, infertility, blindness, and death, accounting for as much as half of koala deaths across wild populations. Professor Peter Timms, who led the research team, emphasized the urgency of the situation: "Some individual wild colonies, where infection rate can be as high as 70 percent, are edging closer to extinction every day."
The current treatment approach using antibiotics has proven inadequate, as these medications can disrupt a koala's ability to digest eucalyptus leaves—their sole source of food—leading to starvation and death. Antibiotics also often fail to prevent future infections, leaving populations vulnerable to recurring disease outbreaks.
Vaccine Development and Clinical Validation
The vaccine development program, spanning more than 10 years, culminated in the largest and longest-ever study of wild koalas, led by UniSC Senior Researcher Dr. Sam Phillips. The comprehensive clinical trials demonstrated significant protective effects, with Dr. Phillips reporting: "This study found it reduced the likelihood of koalas developing symptoms of chlamydia during breeding age and decreased mortality from the disease in wild populations by at least 65 percent."
The vaccine has been extensively tested on hundreds of wild koalas, captive animals in wildlife hospitals, and across multiple generations to establish its safety profile and efficacy. The formulation is based on Chlamydia pecorum's major outer membrane protein (MOMP) and provides three distinct levels of protection: reducing initial infection rates, preventing progression to clinical disease, and in some cases, reversing existing symptoms.
International Collaboration and Technical Innovation
The vaccine development leveraged global expertise and resources, incorporating an adjuvant originally developed by the University of Saskatchewan's Vaccine and Infectious Disease Organization (VIDO), the International Vaccine Institute, the University of British Columbia, and Dalhousie University, with funding support from the Bill and Melinda Gates Foundation.
Key partnerships with organizations including Morris Animal Foundation, Rane Pharma Canada, and global animal health company Ceva Santé Animale provided critical technical expertise and funding through the Ceva Wildlife Research Fund. Pierre-Marie Borne, Director of the Ceva Wildlife Research Fund, highlighted the vaccine's practical design: "The vaccine's design emphasises operational feasibility, requiring a single-dose administration, which is critical in wildlife management to minimize handling stress and logistical constraints for field teams."
Conservation Impact and Future Implementation
Wildlife conservationist Dr. Terri Irwin AM noted the significance of real-world testing conditions: "These trials involved vaccinating koalas in real-world conditions, enabling researchers to gather valuable data on the vaccine's potential benefits." The Australia Zoo Wildlife Hospital contributed to these trials, combining scientific research with compassionate care for affected animals.
The vaccine is being produced in partnership with Australian-owned animal health company Tréidlia Biovet following approval from the Australian Pesticides and Veterinary Medicines Authority. However, Professor Timms acknowledged that significant challenges remain: "There is still much more to be done – including sourcing major funding and donations to enable the national rollout of the approved vaccine at-risk koala populations."
University of the Sunshine Coast Vice-Chancellor Professor Helen Bartlett emphasized the broader significance of this achievement: "This vaccine bridges the gap between discovery and real-world application, translating to a tangible, game-changing product that offers real hope for this endangered species."
The research team continues to refine the vaccine and conduct ongoing studies to ensure long-term effectiveness, while working to secure funding for nationwide distribution to protect Australia's most vulnerable koala populations from this devastating disease.
