Vaccination of koalas with a prototype chlamydial vaccine is safe, does not increase the incidence of lymphoma-related disease and maybe associated with increased lifespan in captive koalas

Koalas vaccinated with a prototype Chlamydia vaccine may live longer than unvaccinated ones. There was no known Chlamydia infection among koalas, so our interpretation is that vaccination may have boosted the innate and adaptive immune systems to protect against a wide spectrum of bacteria, fungi and parasites. Vaccinated koalas did not show negative physiological effects of the vaccine, for example, the frequency of deaths due to lymphomas/neoplasias was the same in both vaccinated and unvaccinated animals.