A koala sits in a tree at a koala park in Sydney, Australia, Friday, May 5, 2023. Australian scientists have begun vaccinating wild koalas against chlamydia in a pioneering field trial in New South Wales. The aim is to test a method for protecting the beloved marsupials against a widespread disease that causes blindness, infertility and death. (AP Photo/Mark Baker)

Australian scientists have begun vaccinating wild koalas against chlamydia in a pioneering field trial in New South Wales. The aim is to test a method for protecting the beloved marsupials against a widespread disease that causes blindness, infertility and death. The safety and effectiveness of the single-shot vaccine has previously been tested by vaccinating koalas individually brought into wildlife rescue centers for other afflictions. Now the scientists want to understand the impact of vaccinating a population of wild koalas. A 2020 government assessment found that koalas could become extinct in the wild by 2050 due to threats from disease, habitat loss and road collisions.