Polio
A vaccine-preventable infection caused by poliovirus that can rarely invade the nervous system and cause permanent paralysis or death.
What causes Polio?
Polio is caused by poliovirus and spreads mainly through the fecal-oral route, especially where sanitation is poor. Oral secretions can also transmit virus early in infection.
Symptoms and what to notice
Most infections cause no symptoms. Some cause fever, sore throat, fatigue, nausea, headache, stomach pain, or meningitis-like neck and back stiffness. Paralytic polio causes sudden weakness, usually asymmetrical.
How long can it last?
Symptoms, when present, often begin 3 to 35 days after exposure. Mild illness lasts days, but paralysis can be permanent. Post-polio syndrome may develop decades after the original infection.
How serious is Polio?
Paralysis can affect limbs or breathing muscles and may be fatal. Even people who initially recover can later develop new weakness, fatigue, or pain through post-polio syndrome.
Treatment and management
No antiviral cures polio. Care includes pain control, physical and respiratory support, prevention of deformity, rehabilitation, and long-term management of weakness or post-polio symptoms.
Vaccine: who and when?
IPOL is the stand-alone inactivated poliovirus vaccine used in the United States. IPV is also included in Pediarix, Pentacel, Vaxelis, Kinrix, and Quadracel. Children routinely receive four IPV-containing doses at 2 months, 4 months, 6-18 months, and 4-6 years. Unvaccinated adults and certain travelers follow catch-up or booster guidance.
Cost note: Patient cost varies by product, provider, insurance, location, and eligibility. Many recommended vaccines are covered in network without cost sharing, and qualifying children may use the Vaccines for Children program.
Trusted source
Patient cost varies by insurance, provider, location, and eligibility. Coverage and public-health access differ, so listed prices are examples rather than guaranteed patient prices. This page is for general education and does not replace individualized medical advice, diagnosis, vaccination assessment, or treatment.
Polio: Symptoms, Causes, Treatment, Prevention, and Vaccine Information
Polio has been eliminated from routine circulation in the United States, but it has not been eradicated globally. Because most infections are silent, a paralysis case can be the first visible signal of broader transmission. Maintaining IPV coverage and vaccinating travelers protects individuals and prevents re-establishment of the virus.
Important: This page is for general education. It does not replace diagnosis, treatment, vaccination advice, or emergency care from a qualified healthcare professional.
Quick Facts
| Topic | Current information |
|---|---|
| Cause | Polio is caused by poliovirus and spreads mainly through the fecal-oral route, especially where sanitation is poor. Oral secretions can also transmit virus early in infection. |
| Main symptoms | Most infections cause no symptoms. Some cause fever, sore throat, fatigue, nausea, headache, stomach pain, or meningitis-like neck and back stiffness. Paralytic polio causes sudden weakness, usually asymmetrical. |
| Typical course | Symptoms, when present, often begin 3 to 35 days after exposure. Mild illness lasts days, but paralysis can be permanent. Post-polio syndrome may develop decades after the original infection. |
| Treatment | No antiviral cures polio. Care includes pain control, physical and respiratory support, prevention of deformity, rehabilitation, and long-term management of weakness or post-polio symptoms. |
| Vaccine status | IPOL is the stand-alone inactivated poliovirus vaccine used in the United States. IPV is also included in Pediarix, Pentacel, Vaxelis, Kinrix, and Quadracel. Children routinely receive four IPV-containing doses at 2 months, 4 months, 6-18 months, and 4-6 years. Unvaccinated adults and certain travelers follow catch-up or booster guidance. |
History and Public-Health Importance
Large twentieth-century epidemics caused paralysis and fear until inactivated Salk vaccine and oral Sabin vaccine transformed prevention. The Americas were certified free of wild poliovirus in 1994. The United States now uses only inactivated vaccine, which cannot cause polio. Global eradication has been slowed by persistent wild-virus transmission and outbreaks from vaccine-derived strains where immunity is low.
What Causes Polio?
Polio is caused by poliovirus and spreads mainly through the fecal-oral route, especially where sanitation is poor. Oral secretions can also transmit virus early in infection.
Infected people shed virus in stool for weeks and can transmit it without symptoms. Poor sanitation and inadequate vaccination enable spread. Oral polio vaccine used in some countries can rarely mutate during prolonged circulation in undervaccinated communities; this is why strong population immunity is essential.
Symptoms and Typical Course
Most infections cause no symptoms. Some cause fever, sore throat, fatigue, nausea, headache, stomach pain, or meningitis-like neck and back stiffness. Paralytic polio causes sudden weakness, usually asymmetrical.
Most infections remain asymptomatic. Abortive illness resembles a mild viral syndrome, while nonparalytic infection causes meningitis symptoms. Paralytic disease produces acute flaccid weakness with reduced reflexes and preserved sensation. Bulbar involvement can impair swallowing and breathing. Recovery varies with the number of motor neurons damaged.
Complications and Who Is at Higher Risk
Paralysis can affect limbs or breathing muscles and may be fatal. Even people who initially recover can later develop new weakness, fatigue, or pain through post-polio syndrome.
Permanent limb weakness, deformity, breathing failure, swallowing problems, and death are possible. Decades later, some survivors develop post-polio syndrome with new weakness, fatigue, and pain. This is not reinfection and is not contagious.
How It Is Diagnosed
Suspected acute flaccid paralysis requires immediate public-health notification. Testing may include stool and respiratory specimens for poliovirus PCR and culture, plus cerebrospinal fluid and imaging to evaluate alternative causes. Multiple stool specimens collected promptly improve detection.
Treatment and Recovery
No antiviral cures polio. Care includes pain control, physical and respiratory support, prevention of deformity, rehabilitation, and long-term management of weakness or post-polio symptoms.
Supportive treatment prevents secondary damage. Ventilatory support may be lifesaving, while physical therapy preserves motion and function without overfatiguing weakened muscles. Orthopedic, respiratory, speech, and rehabilitation specialists may be needed. Antibiotics do not treat poliovirus.
Vaccine Information
IPOL is the stand-alone inactivated poliovirus vaccine used in the United States. IPV is also included in Pediarix, Pentacel, Vaxelis, Kinrix, and Quadracel. Children routinely receive four IPV-containing doses at 2 months, 4 months, 6-18 months, and 4-6 years. Unvaccinated adults and certain travelers follow catch-up or booster guidance.
IPOL contains killed virus types 1, 2, and 3. Combination products provide IPV with other childhood antigens. The final childhood dose should be given at age four or older and at least six months after the previous dose. Adults known or suspected to be unvaccinated should complete a primary IPV series; fully vaccinated adults at increased exposure risk may receive one lifetime booster.
Prevention
Complete the IPV series, verify vaccination before travel to affected areas, use safe water and sanitation, and report acute flaccid paralysis promptly. Travelers may need documentation under international rules for certain destinations.
When to Seek Medical Care
Seek emergency care for sudden limb weakness, difficulty breathing or swallowing, severe neck or back stiffness, or weakness after travel or exposure. Clinicians should notify public health immediately.
Frequently Asked Questions
Can IPV cause polio?
No. IPV uses killed virus and cannot cause poliomyelitis.
Is polio gone from the world?
No. Wild virus still circulates in limited areas, and vaccine-derived outbreaks can occur where coverage is low.
Do adults need polio vaccine?
Most vaccinated U.S. adults do not need routine boosters, but unvaccinated adults and certain travelers or workers do.
What is post-polio syndrome?
It is new weakness or fatigue years after paralytic polio; it is not contagious and is not a new infection.
Key Takeaway
Polio can spread silently and cause irreversible paralysis. Complete IPV vaccination and rapid investigation of acute weakness keep elimination secure.
Medical, treatment, and vaccine information was reviewed against official U.S. public-health guidance available through September 2026.