What Is Poliomyelitis (Polio)?
A highly infectious viral disease that can cause irreversible paralysis, targeted for global eradication through vaccination.
Pathogen: Poliovirus (types 1, 2, 3 — Enterovirus genus, Picornaviridae family). Only wild type 1 remains in circulation. Circulating vaccine-derived poliovirus (cVDPV) type 2 is also a concern.
Type: Virus
Transmission
Faecal-oral route (predominant in areas with poor sanitation) and oral-oral route. The virus is shed in faeces for weeks and can contaminate water and food. Highly infectious — asymptomatic carriers spread the virus.
Vector: No arthropod vector. Faecal-oral and oral-oral transmission.
Symptoms
Most infections (>90%) are asymptomatic. Minor illness (5-10%): fever, headache, sore throat, nausea, and vomiting. Non-paralytic meningitis (1-2%): neck stiffness, back pain. Paralytic polio (<1%): acute flaccid paralysis, typically asymmetric, affecting the legs more than arms. Bulbar polio affects breathing and swallowing muscles.
Incubation period: 7 – 21 days
Usually 7-10 days for minor illness, 7-21 days for onset of paralysis. Over 90% of infections are asymptomatic.
Timeline: Minor illness appears 3-5 days after infection and resolves within days. Paralysis, when it occurs, develops over 1-10 days. Maximum paralysis is usually reached within 3-4 days. Some recovery may occur over weeks to months, but residual paralysis is permanent.
Case fatality rate: 2-5% in children with paralytic polio, 15-30% in adults. Higher for bulbar polio (affecting breathing). Case fatality has been reported up to 60% in some outbreaks when respiratory support is unavailable.
Diagnosis & Treatment
Diagnosis: Virus isolation from stool (gold standard — 2 stool samples 24-48 hours apart), throat swab, or CSF. PCR for poliovirus detection and typing. Acute flaccid paralysis (AFP) surveillance is the primary tool for detecting polio cases globally.
Treatment: No cure for polio. Treatment is entirely supportive: bed rest, pain management, physical therapy, mechanical ventilation for respiratory paralysis. Long-term rehabilitation and assistive devices for permanent paralysis. Post-polio syndrome can develop decades later.
Prevention
- Polio vaccination (IPV — inactivated polio vaccine, or OPV — oral polio vaccine)
- Booster dose before travel to endemic or outbreak countries if more than 10 years since last dose
- Safe water and food hygiene practices
- Hand washing with soap after toilet use and before eating
💉 Vaccine Available
A vaccine is available for Poliomyelitis (Polio). View the Polio vaccine guide for details on schedule, cost, and availability in Australia.
Post-Exposure
If you have been in a country with active polio circulation and are not up to date with vaccination, consult your GP for a booster. There is no post-exposure prophylaxis, but ensuring vaccination is current is the priority.
Long-Term Effects
Permanent paralysis occurs in those with paralytic polio. Post-polio syndrome can develop 15-40 years after the original infection, causing progressive muscle weakness, fatigue, and pain. It affects 25-40% of polio survivors.
📋 Poliomyelitis is a nationally notifiable disease in Australia. Australia has been polio-free since 1972 (wild poliovirus) but maintains surveillance. A booster is recommended for travellers to endemic or outbreak countries.
Frequently Asked Questions
Am I already vaccinated for polio?
If you grew up in Australia, you almost certainly received the polio vaccine as part of the childhood immunisation schedule (at 2, 4, 6 months and 4 years). However, immunity can wane over decades. If you are travelling to a country with active polio circulation and it has been more than 10 years since your last polio vaccine, a single booster dose of IPV is recommended.
Which countries still have polio?
As of 2026, wild poliovirus type 1 remains endemic in Pakistan and Afghanistan. However, circulating vaccine-derived poliovirus (cVDPV), mostly type 2, has been detected in multiple countries across Africa, the Middle East, Southeast Asia, and the Pacific. Check the Global Polio Eradication Initiative (polioeradication.org) and Smartraveller for the latest affected countries before travel.
Do I need a polio booster for travel to Southeast Asia?
A polio booster may be recommended depending on your specific destination. Some countries in Southeast Asia and the Pacific (including Indonesia, Philippines, Myanmar, Papua New Guinea) have reported circulating vaccine-derived poliovirus. If it has been more than 10 years since your last polio vaccine, discuss a booster with your travel doctor.
Do any countries require proof of polio vaccination?
Yes. Some countries with polio outbreaks require travellers to show proof of polio vaccination for entry or on departure. For example, Pakistan requires all arriving and departing travellers to have documented polio vaccination. Requirements change based on outbreak status — check current requirements for your destination. Proof is recorded on the International Certificate of Vaccination (yellow card).
Is polio eradicated?
Not yet. Wild poliovirus types 2 and 3 have been eradicated (certified 2015 and 2019 respectively), but wild type 1 persists in Pakistan and Afghanistan. Additionally, circulating vaccine-derived poliovirus (cVDPV) outbreaks continue in multiple countries. The Global Polio Eradication Initiative is working toward full eradication, but continued vaccination remains essential.
What is vaccine-derived poliovirus?
In areas with low vaccination coverage, the weakened virus in the oral polio vaccine (OPV) can circulate in the community and, over time, mutate back to a form that can cause paralysis. This is called circulating vaccine-derived poliovirus (cVDPV). It is a consequence of under-vaccination, not of vaccination itself. The inactivated polio vaccine (IPV) used in Australia cannot cause this.
Can adults get polio?
Yes. While polio is most commonly associated with children, adults can be infected and paralysed, particularly if they are unvaccinated or under-vaccinated. In fact, paralytic polio has a higher fatality rate in adults (15-30%) than in children (2-5%). Adults travelling to endemic areas should ensure their polio vaccination is up to date.
What is post-polio syndrome?
Post-polio syndrome (PPS) is a condition that affects 25-40% of polio survivors, typically 15-40 years after the original infection. Symptoms include new or worsening muscle weakness, fatigue, joint pain, and reduced function. It is not caused by reinfection with poliovirus but by the gradual deterioration of motor neurons that were damaged during the original infection.
Sources & References
Last updated: April 2026