A strain of poliovirus has been discovered in the wastewater samples of Perth, which is the first detection of the virus in Australia via environmental monitoring techniques.
There have been no human infections associated with the findings and the officials reiterated that Australia is still a polio free nation.
The national polio surveillance system discovered that there is a vaccine derived poliovirus type 2 in the untreated wastewater from the Subiaco wastewater treatment plant during mid April.
This finding was made on 27 April, and the WHO has been informed through International Health Regulations reporting requirements.
Polio has never been acquired in Australia since 1972, and it has been declared a polio free region by the World Health Organization since 2000.
The discovery highlights that the polio virus is still present in the community, although no person has contracted the infection.
According to Dr Clare Huppatz, Chief Health Officer in Western Australia, the discovery poses minimum risks to the public.
She mentioned that 92% of children in Western Australia have received a poliovirus vaccination.
Approximately 93% of five year olds in the country have received all recommended vaccinations against polio, falling short of the global target of 95%.
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State and federal health officials believe that the most plausible explanation is that the virus was contracted while in Perth by an international traveler.
A rare strain of poliovirus known as “vaccine derived poliovirus” can appear in nations that continue to use oral polio vaccines, which contain a weakened live virus.
Since Australia switched to an injectable, inactivated vaccine years ago, this kind of strain cannot be produced by the country’s immunization program.
Professor Zoe Wainer, the Director General of the Australian Centre for Disease Control, noted in a statement that “This is an environmental detection, not a clinical case.”
Families were advised to verify the status of their vaccinations and contact a doctor in case there were any doubts regarding booster shots.
This came after an incident that took place in Melbourne in 2024, where a vaccine derived polio virus type 2 was detected through wastewater sampling.
After the discovery of this case in Perth, the WA Department of Health has decided to increase the frequency of testing of wastewater samples and collaborate with clinicians from hospitals.
The disease itself, poliomyelitis, can cause paralysis and, in rare cases, death, especially in children.
Wild virus types 2 and 3 have been eradicated globally but vaccine derived outbreaks persist in some areas of Africa and the Asia Pacific region.
Free polio vaccination is available to children at scheduled ages through the National Immunisation Program, and to eligible people under 20 years of age who require catch up dose and refugees and humanitarian entrants of any age.
Parents can check immunisation records on MyGov or with their local provider.
