Polio and Post-Polio Syndrome: How Polio Spreads, Its Symptoms, Vaccines and Later Effects

Polio (poliomyelitis) is a disease caused by the poliovirus, which spreads from person to person and attacks the nervous system. In serious cases it causes paralysis — being unable to move parts of the body — which may be lifelong and sometimes life-threatening.

Thanks to vaccines, polio is rare in the United States, but it still occurs in some parts of the world, and travelers can spread it.

How it spreads

The poliovirus is very contagious. It spreads through contact with the stool (poop) of an infected person, or droplets from their sneeze or cough — for example when:

• you get contaminated stool or droplets on your hands and then touch your mouth;
• a child puts contaminated toys or other objects in their mouth;
• you share food or utensils with someone infected.

People can spread it from just before symptoms appear to several weeks after. People with no symptoms can still pass it on and make others sick.

Who is at risk

Polio mainly affects children under 5, but unvaccinated people of any age, adults included, can get it. The risk is higher for anyone who lives in or travels to places where polio occurs.

Symptoms

Most people infected have no symptoms. About one in four get flu-like symptoms lasting 2 to 5 days:

• sore throat; fever; fatigue;
• nausea; headache; stomach pain.

Rarely, polio is very serious. It can lead to:

• meningitis — an infection of the covering of the spinal cord and/or brain;
• weakness or paralysis in the arms, legs or both, which can last a lifetime, and can be life-threatening if it reaches the muscles used for breathing;
• post-polio syndrome later in life.

Post-polio syndrome (PPS)

PPS affects polio survivors many years after they recovered — usually 15–40 years later. It is not contagious. Muscles that polio affected before start to weaken again, mildly or seriously:

• muscle weakness, atrophy (wasting) and loss of function;
• mental and physical fatigue;
• joint pain;
• curving of the spine (scoliosis).

PPS is rarely life-threatening, but it can get in the way of daily life.

Diagnosis

If you think you or someone in your family has polio symptoms, call your health care provider right away or go to an emergency room. The provider will:

• do a physical exam;
• take a detailed medical history, including vaccinations and recent travel;
• collect samples such as stool, saliva, blood, urine and spinal fluid — the virus is most likely found in stool;
• perhaps order an MRI to look at the spinal cord.

Treatment

There is no cure and no specific treatment for polio. For a mild case, rest and plenty of fluids may ease some symptoms. A serious case may need:

• physical or occupational therapy for arm or leg weakness — the earlier, the better;
• pain relievers for pain and fever — but don't give a child aspirin unless their provider says to;
• a ventilator if the breathing muscles are weak or paralyzed.

There is also no cure for PPS, but treatment can help manage it:

• non-fatiguing exercises — ones that don't cause pain or fatigue lasting more than 10 minutes — which may build strength and reduce tiredness; your provider can help choose them;
• mobility aids and ventilation equipment;
• healthy eating, enough sleep and not smoking.

Prevention

• Children in the United States get four doses of IPV as routine childhood shots.
• Most U.S. adults were vaccinated as children.
• A one-time IPV booster may be given to fully vaccinated adults at higher risk — people traveling to a country where polio risk is greater, laboratory or health care workers handling samples that might contain poliovirus, and health care workers in contact with patients who could have polio.

Wash your hands often with soap and water — alcohol-based hand sanitizers don't kill poliovirus.

Sources

Based on "Polio and Post-Polio Syndrome," MedlinePlus, U.S. National Library of Medicine, with information from the Centers for Disease Control and Prevention; a work of the United States government in the public domain. The source's "four doses of PV" is read as IPV, the only polio vaccine it says the United States uses.