‘It’s difficult to catch a koala’: how will Australia’s newly approved koala chlamydia vaccine work?

September 15th, 2025

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 “heartbreaking” situation.

Crucially, no booster shot is required, giving researchers hope that the vaccine can eventually be used in the wild. “It’s difficult to catch a koala once, let alone two or three times,” says Dr Sam Phillips, a microbiologist who has spent almost a decade working on the vaccine.

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 “a huge, devastating issue”.