We successfully eliminated polio across Australia by the year 2000, only to see it return recently from Papua New Guinea. Still, this resurgence has health officials sounding the alarm. This resurgence takes place amidst a severe and continuing global drop in the incidence of polio and in vaccination campaigns against it. Since the launch of the Global Polio Eradication Initiative in 1988, polio has decreased by an incredible 99% around the world. The recent emergence of vaccine-derived poliovirus in Australia’s nearest neighbor has brought concerns of future outbreaks back to the forefront.
Polio, a highly infectious viral disease spreads through contaminated water, can lie dormant for up to 35 days. Three quarters of all infections are completely asymptomatic. In exceptional situations, they can lead to acute flaccid paralysis in less than one of each hundred contaminated individuals. When symptoms come they can be completely debilitating. Fever, fatigue, nausea, vomiting, sore throat and weakness of muscles can last for nine to ten days starting from infection.
Australia has not had a significant polio outbreak since 1961. Vaccination remains an important aspect of the country’s routine immunization schedule for infants. Despite this, recent statistics reveal a concerning trend: vaccination rates against polio have slightly declined in recent years.
Declining Vaccination Rates
In 2023, Australia’s polio vaccination coverage for one-year-old children was 91.6%. This is a decrease from the 94.8% observed in 2020. Likewise, the share of two-year-old children fully vaccinated dropped to 89.4%, a decline from 92% four years earlier. Among five-year-old children, the rate is at 92.7%, as well below the 2020 numbers.
Linda Selvey, an expert in infectious disease at Curtin University, told the Guardian that the downward trend in vaccination numbers was “deeply alarming”.
“We’re only at risk if we have a population who’s not immune. Generally, I think our immunisation coverage in Australia is still pretty good, even though it has fallen in the last few years.” – Linda Selvey
Selvey acknowledged that Australia has strong sanitation measures and low population density working in their favour. Areas in the vicinity of Papua New Guinea could be at even greater risk.
“The greatest risk would be in the parts of Queensland, in particular in the Torres Strait, where there’s closer movement of people between Papua New Guinea and Australia and also where the housing and so on is less optimal.” – Linda Selvey
Papua New Guinea is paying a high price for its poor immunization rates. Insufficient health infrastructure adds to this issue, possibly enabling polio cases remaining hidden from surveillance.
“I’m concerned about the outbreak from the perspective of the people in Papua New Guinea in particular because they generally have very low immunisation coverage,” – Linda Selvey
Global Context and Australia’s Response
Despite significant progress in eradicating polio globally—type 2 has been officially eradicated for 26 years and type 3 for five—polio remains endemic in Afghanistan and Pakistan. The World Health Organization (WHO) followed suit with a dire warning that “Polio everywhere is a threat everywhere.” This powerful statement reminds us of the interconnectedness of our health systems around the globe and the need for concerted, cooperative vaccination efforts.
Following the recent re-emergence of the poliovirus variant in Papua New Guinea, Australian authorities are moving quickly to protect their population. Ray Adams, a spokesperson for DFAT, further assured that Australia was already working closely with the Papua New Guinea government. Together, they’re joining WHO and UNICEF in calling to end this avoidable public health crisis.
“Australia is working closely with Papua New Guinea, the World Health Organization and UNICEF to help respond to the detection of vaccine-derived poliovirus,” – A DFAT spokesperson
The government’s spokesperson explained their intense focus on supporting Papua New Guinea’s National Polio Response Plan. This support will take the form of specialized, targeted technical assistance.
“We’re supporting PNG’s National Polio Response Plan, including through targeted technical assistance.” – A DFAT spokesperson
Surveillance Challenges
Despite these efforts, experts continue to sound the alarm on the major gaps in our surveillance systems for vaccine-preventable diseases like polio. Dr. Huseynova highlighted how these gaps make the already difficult job of health officials even more daunting.
“The surveillance systems gaps for vaccine-preventable diseases, including acute flaccid paralysis — which is the gold standard for polio detection — further worsen the problem,” – Dr Huseynova
These surveillance challenges make it more difficult and slower to detect and respond to potential outbreaks, putting people at greater risk for the spread of disease. Vaccination rates are falling nationwide. At the same time, other countries are experiencing their own vaccination crises, which underscores the need for all countries to sustain high immunization coverage.
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