Victoria's unique environmental testing program has detected poliovirus in pre-treated sewage from the Western Treatment Plant in Melbourne.
Victoria's acting Chief Health Officer, Dr Brett Sutton, said the virus was detected in tiny concentrations as part of routine environmental surveillance in Victoria that supports the Global Polio Eradication Initiative.
"This does not mean someone has polio. Rather it is likely to have come from a person who received live vaccine in another country and has continued to excrete it since arriving in Victoria,' Dr Sutton said.
"There are currently no cases of polio in Australia. The last case of polio was in 2007 in a traveller who acquired the infection in Pakistan. Victoria hasn't had a locally acquired case since the 1970s.
"Genetic analysis has now been completed, identifying the virus as a rare type 2 poliovirus.
"There is an extremely low risk that the detection of this poliovirus will cause disease in anyone.
"Firstly, poliovirus usually doesn't cause illness even when infection occurs. Secondly, this poliovirus was found at concentrations that do not cause infection. Finally, Australia has very high immunisation coverage and excellent sanitation infrastructure that prevents people being exposed to sewage," Dr Sutton said.
Australia, through the National Immunisation Program provides a free polio vaccine at 2, 4 and 6 months of age. A booster dose is provided at 4 years of age.
An inactivated polio vaccine is used in Australia, which means it cannot multiply in a person, is not found in the bowel or sewage and cannot cause polio disease.
Polio immunisation coverage in Victoria is above 95 per cent for children at five years of age -- amongst the highest in the country.
In addition, from July 2017 everyone up to the age of 19 years and refugees and humanitarian entrants of all ages have been eligible to receive three doses of polio vaccine as part of catch up arrangements.
Dr Sutton said this high level of immunisation in children and adults makes any risk of polio occurring in Victoria extremely low.
"Further testing of sewage samples from the Western Treatment Plant in Melbourne will happen for the foreseeable future to monitor the situation.
"However, this is a timely reminder, especially for children, to be immunised so they can be protected from all serious diseases, whether common or rare," Dr Sutton said.
Reviewed 15 December 2017