A highly contagious and lethal poliovirus, not seen in Australia for over 54 years, has been identified in sewage samples from Perth. Health authorities reported the detection of this vaccine-derived strain in untreated wastewater at the Subiaco treatment plant mid-April, marking the first time this specific strain has been found in the country. Similar findings were previously noted in Europe in 2024 and 2025, but those instances did not result in any recorded cases of polio.
According to the Australian Centre for Disease Control (CDC), the strain likely originated from a traveller arriving from overseas. Vaccine-derived poliovirus is uncommon but can surface in areas where oral polio vaccines are administered; however, Australia does not use these vaccines. Despite the significant nature of this detection, health officials clarified that it does not indicate the emergence of polio within the local population.
Professor Zoe Wainer, Director-General of the Australian CDC, emphasised that the wastewater surveillance system is designed to provide early warnings, allowing health authorities to take preemptive measures. She confirmed that no clinical cases of polio have been reported, and there is no evidence of local transmission. The Western Australian government will enhance testing frequency at the Subiaco plant, increasing it to weekly for the next six months. The last locally-acquired polio case in Australia occurred in 1972.
Polio, a highly infectious viral illness primarily affecting children under five, can result in paralysis and death. Although Australia has been polio-free since 2000, the global health goal is for at least 95% vaccination coverage among children, while Australia currently rates at approximately 93%. The country has an effective polio vaccine that protects against types 1, 2, and 3.
In closing, while this detection in Perth is concerning, Wainer reassured the public that it should not affect Australia’s polio-free status, and continued vigilance in monitoring wastewater will help safeguard public health.