Melbourne Detects Vaccine-Derived Poliovirus

The Victorian Department of Health recently announced that Australia's surveillance program detected vaccine-derived poliovirus type 2 (VDPV2) in pre-treated sewage from the Western Treatment Plant in Melbourne.

Melbourne has over 5 million residents and is the host city of the Australian Open 2025, which hundreds of thousands of tennis fans attend.

The poliovirus detection (Advisory number: 241224) on December 2, 2024, is likely linked to an individual who received a live polio vaccine and shed the virus in Victoria. Victoria's Chief Health Officer, Dr. Clare Looker, wrote on December 23, 2024, that Australia remains polio-free, as this wastewater detection is not a wild-type poliovirus case.

However, the U.S. CDC says the detection of poliovirus in wastewater cannot be used to determine the total number of infected persons in a community or the portion of the infected population. The minimum number of infected individuals that can be reliably detected through wastewater testing is not known.

To alert the international community, the World Health Organization (WHO) confirmed in December 2024 that the spread of the poliovirus remained a Public Health Emergency of International Concern. In 2022, the United States was added to the WHO's list of polio-identified countries. 

Over the past few years, more than 1 billion 'triple-locked' nOPV2 vaccines have been administered to prevent virus mutations.

In the United States, the inactivated polio vaccine is offered.

"Most travelers to Australia don't need many travel vaccines, but with poliovirus detected in sewage in Melbourne, a once-in-a-lifetime booster dose of polio vaccine would be prudent before departure," commented Beverly Schaefer, travel vaccine expert at Katterman's Sand Point Pharmacy, Seattle, WA.

The U.S. CDC suggests that international travelers speak with a travel vaccine expert about Japanese encephalitis, which is mainly a concern in the Murray River and the Outer Torres Strait Islands area. All international travelers should also be vaccinated against measles with the MMR vaccine.