Polio for health professionals

Polio is a highly contagious, vaccine-preventable viral infection caused by poliovirus. It is a nationally notifiable disease. We monitor and report on national case numbers and epidemiological trends. We publish case definitions and guidelines to support health professionals and health authorities.

For health professionals For everyone

Disease

  • Poliovirus has 3 serotypes: types 1, 2 and 3. Type 1 is the most virulent and widespread, responsible for most paralytic polio cases and epidemics. Type 3 was declared globally eradicated in 2019.

    Polioviruses can be categorised into:

    • wild-type (naturally occurring) polioviruses
    • vaccine-related poliovirus strains (live-attenuated oral poliovirus vaccine [OPV] viruses)
    • vaccine-derived polioviruses, arising from OPV strains.[1]

    Vaccine-derived poliovirus can circulate in under-immunised populations, particularly in areas where OPV is still used. Australia now exclusively uses the inactivated poliovirus vaccine, rather than OPV.

    Humans are the only known natural host and reservoir of polioviruses.

  • At least 95% of polio cases are asymptomatic.[2]

    There are different clinical types of polio, which range in severity.

    Abortive polio occurs in about 4% to 8% of cases. In this type of polio, there is no neurological involvement. Clinical features are mild and self-limiting such as:

    Non-paralytic polio is more severe than abortive polio and can present with signs of meningeal irritation, such as:

    • neck stiffness
    • severe headache
    • limb pain.

    Non-paralytic polio usually resolves within 1 to 2 weeks but a very small proportion of cases progress to paralytic polio.

    In paralytic polio, additional clinical features include:

    • severe myalgia (muscle pain)
    • cutaneous hyperesthesia (increased skin sensitivity)
    • paraesthesia (abnormal sensation)
    • involuntary muscle spasm
    • flaccid paralysis.

    Paralysis develops over 2 to 3 days, with legs more commonly affected than arms. Severity ranges from partial involvement of one muscle to complete quadriplegia. About 2 in 3 people with acute flaccid paralysis will not regain full strength.

    Other serious complications can include:

    • respiratory compromise
    • myocarditis
    • gastrointestinal complications, such as bleeding and bowel obstruction.

    Post-polio syndrome can occur years after initial infection in people who partially or fully recovered.

    Read more about symptoms, diagnosis and treatment of polio

Public health importance

  • Polio is a serious viral disease that can lead to long-term disability, paralysis and death. There is no cure, but it is preventable with a safe and very effective vaccine. 

    Before the introduction of widespread vaccination, polio was a major global health problem. In 1988, the World Health Assembly adopted a Global Polio Eradication Initiative. Since then, the global incidence of polio has decreased by 99%.

    In Australia, the risk of polio is low. Australia maintains high polio vaccination coverage through the National Immunisation Program.

    The World Health Organization has declared the risk of international spread of poliovirus constitutes a Public Health Emergency of International Concern.

    Because of this, we:

  • Australia, along with the WHO Western Pacific Region, was verified as polio-free in 2000. 

    Since 1987, only one case of polio caused by wild poliovirus has been reported in Australia. This case occurred in 2007 in a person who acquired their infection in Pakistan.[3] 

    No locally acquired cases of polio have been reported in Australia since the 1970s.

    Globally, wild poliovirus remains endemic in Pakistan and Afghanistan.

    The death rate for paralytic polio is:

    • up to 5% for children
    • 15% to 30% for adults.[4]

    In Australia, deaths caused by polio have been rare since the 1950s.[5]

    For the latest information on poliovirus cases in Australia see the:

Spread of infection

  • Poliovirus is highly contagious. It mainly transmits through the faecal–oral route. 

    Less often, transmission can occur through saliva or respiratory secretions.

    Poliovirus can survive outside the human body for several weeks.

  • Symptoms, if present, usually start between 7 and 14 days after exposure to the virus, but this can range from 2 to 35 days.

  • Cases are infectious from about 7 to 10 days before the onset of symptoms. 

    Cases are usually most infectious in the days immediately before and after the onset of symptoms, but asymptomatic cases are also infectious. 

    The virus may be present in the faeces for many weeks.[2]

    People who are immunocompromised might shed the virus for longer.

Priority populations

  • People at greater risk of severe disease and complications from polio may include those who are:

    • unvaccinated
    • infants or young children
    • pregnant
    • immunocompromised.

    See what measures people can take to protect themselves.

  • People are more likely to be exposed to the virus if they:

    See what measures people can take to protect themselves.

  • Settings at increased risk of poliovirus spread include:

    • households, especially if overcrowded
    • early childhood education and care centres
    • residential care facilities
    • settings with poor sanitation, such as reduced access to hand-washing facilities or inadequate sewage treatment.

Prevention

  • Polio vaccination is provided free under the National Immunisation Program. The inactivated polio vaccine (injectable) is safe and highly effective.

    Vaccination against polio is recommended for all:

    • infants and children from 2 months of age
    • adolescents and adults who have never received the polio vaccine.

    An additional dose of polio vaccine is recommended every 10 years for:

    • healthcare workers who may have contact with people with polio
    • laboratory workers who may have contact with poliovirus
    • travellers to areas or countries with polio cases.

    See the Australian Immunisation Handbook for more information, and who is eligible for free polio vaccination under the National Immunisation Program.

  • People who may be exposed to poliovirus through their work must follow their workplace health and safety advice.

    Control of polio relies on effective surveillance and outbreak response activities. 

    Read more about global efforts to eradicate polio.

Diagnosis and clinical management

  • Polio is diagnosed through laboratory testing in patients presenting with clinical features suggestive of the disease. 

    A sample of faeces is usually used for diagnosis. 

    Nucleic acid amplification testing (such as polymerase chain reaction or PCR) is routinely used to detect enteroviruses. 

    In clinically compatible cases, specimens are referred for further testing for poliovirus at the National Enterovirus Reference Laboratory (NERL) in Melbourne. This includes culture and whole genome sequencing. 

    Under the Global Polio Eradication Initiative, all polioviruses need to be physically contained in designated poliovirus essential facilities (PEF). The NERL is Australia’s PEF. 

    Polioviruses and any material potentially infectious for poliovirus – like faeces – must not be handled outside of a PEF.

  • Read more about laboratory testing and the laboratory case definition. 

  • The clinical management of polio is largely supportive and includes pain management and physiotherapy.

    Mechanical ventilation may be required where respiratory failure develops. 

    There are no approved antiviral therapies for polio. 

Notification and reporting

Public health response

  • The Poliovirus detection outbreak response plan for Australia outlines the response actions required for a suspected polio case or wastewater detection. 

  • Public health authorities urgently investigate all confirmed and probable polio cases. Case management focuses on:

    • identifying the likely source of infection
    • identifying any contacts
    • preventing transmission.

    People with polio who are infectious are isolated for at least 14 days from onset of symptoms until they have fully recovered.

     Two negative stool samples collected 7 days apart are needed to confirm a person with polio is no longer infectious.

    Hospitalised polio cases are cared for using standard contact and droplet precautions. 

    Read more about:

  • Public health units undertake contact tracing to:

    • identify all potentially infected individuals
    • provide advice and public health education.

    Priority is given to managing contacts who work in settings where they could potentially spread the virus to many people – such as healthcare, childcare and food handling settings.

    Unvaccinated contacts are recommended to get vaccinated. Contacts who have not had a polio vaccine dose within the previous 10 years are offered a booster dose.

    Quarantine for 7 days may be recommended for some contacts, depending on their exposure.

    All contacts are provided with information about polio including: 

    Read more about how polio contacts are managed.

  • Any detection of polio is considered a national public health emergency, requiring a rapid response. The primary goal of the response is containment of potential poliovirus spread.

    Response actions might include:

    • case and contact management
    • targeted immunisation campaigns
    • providing education to cases, contacts and the broader community
    • infection control measures
    • managing potential environmental contamination
    • enhanced surveillance measures
    • notifying the World Health Organization.

    Public health units refer to the Poliovirus detection outbreak response plan for Australia and their state or territory control guidelines when responding to polio. 

  • Laboratory personnel exposed to poliovirus during a high-risk laboratory incident are quarantined for 7 days.

    Read more in the Poliovirus detection outbreak response plan for Australia.

Resources

References

We are adding new content to this website and expanding these pages, including a suite of disease-related information. In the meantime, information about diseases in Australia is available on the Department of Health, Disability and Ageing’s website. 

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