Vaccine-Derived Poliovirus Detected in Perth Wastewater, Officials Say Risk Low

Key facts

• Poliovirus detected in wastewater sample from Subiaco treatment plant in Perth.
• Strain identified as vaccine-derived poliovirus Type 2.
• First detection of this strain in Australia.
• WA chief health officer Dr Clare Huppatz says risk very low due to 92% vaccination coverage in WA children.
• Similar detections in Europe during 2024-2025 did not lead to any disease cases.
• WA Health increasing frequency of wastewater poliovirus testing in Perth metro area.
• similar detections recently in Australia.

Detection Triggers Monitoring Boost

Western Australian health authorities have detected a vaccine-derived strain of poliovirus in wastewater from the Subiaco treatment plant in Perth, prompting an increase in testing frequency across the metropolitan area. The sample, collected in mid-April, contained a Type 2 vaccine-derived poliovirus similar to strains previously identified in Africa, Europe and Papua New Guinea. WA's chief health officer, Dr Clare Huppatz, said it was the first time this particular strain had been found in Australia. She emphasised that the risk to the public is very low given the state's high vaccination rates.

Source Likely an Overseas Traveller

Dr Huppatz said the finding most likely came from someone who had travelled overseas and was shedding the virus strain. “This sort of detection has occurred in Europe on several occasions across four different countries where this same strain has been detected in the wastewater,” she said. “On each of those occasions it hasn't led to outbreaks, in fact it hasn't led to any single cases of disease.” The detection serves as a reminder, she added, that polio still circulates globally and could be brought to Australia via international travel.

Vaccination Coverage Provides Strong Protection

The poliovirus vaccination coverage among WA children stands at 92 per cent, a level that Dr Huppatz said makes it very unlikely the strain will circulate in the community. “The potential for this strain to circulate in a highly vaccinated population is very low,” she stated. Health officials noted that similar wastewater detections in Europe during 2024 and 2025 did not lead to any cases of polio disease, underscoring the effectiveness of high immunisation rates in preventing outbreaks.

Recent Similar Detections in Australia

University of New South Wales medical epidemiologist Dr Abrar Chughtai said there had been similar detections of poliovirus in Australia recently, though he did not provide specific locations or dates. The WA Health Department is now increasing the frequency of wastewater poliovirus testing in the Perth metropolitan area to monitor for any further signs of the virus. Australia has not recorded a case of polio contracted within the country for 54 years, thanks to widespread vaccination and robust surveillance.

Global Context and Ongoing Risk

Polio remains endemic in Afghanistan and Pakistan, and vaccine-derived outbreaks have occurred in several countries with low immunisation coverage. The World Health Organization continues to classify the risk of international spread as a public health emergency of international concern. Dr Huppatz stressed that the Perth detection was a “timely reminder” that polio virus is still circulating around the world and that with international travel, exposure remains possible even in highly vaccinated regions like Australia.

No Change to Vaccination Recommendations

WA Health has not announced any changes to the current vaccination schedule or travel advisories. Officials continue to recommend that all individuals, especially those travelling to areas where polio is circulating, be fully vaccinated. The detection in Perth wastewater, while not a cause for alarm, highlights the importance of maintaining high vaccination coverage and robust environmental surveillance to quickly identify any potential reintroduction of the virus.

The bottom line

• Vaccine-derived poliovirus Type 2 detected in Perth wastewater, first such finding in Australia.
• WA Health increasing testing frequency but says risk very low due to 92% child vaccination coverage.
• Similar detections in Europe did not lead to any disease cases, providing reassurance.
• Source likely an overseas traveller shedding the virus; no evidence of local transmission.
• Australia has had no domestically acquired polio case for 54 years.