Polio

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is polio?

Polio, or poliomyelitis, is an infectious viral disease caused by the polio virus that can affect many parts of the body. Polio was a global epidemic and a leading cause of disability until a vaccine was developed in the 1950s. In the Western world, the disease was mostly eradicated by the late 1970s, although it still affects developing countries (Source: PubMed).

The polio virus is highly contagious and is transmitted among people through saliva, feces, or person-to-person contact. People living in or traveling to areas of outbreak are susceptible to infection, as are those who have never been immunized with the polio vaccine.

Symptoms of polio are generally categorized by the three patterns of infections: subclinical infections, nonparalytic infections, and paralytic infections. Subclinical infections may not produce symptoms at all, and polio infection usually does not progress beyond this stage or cause symptoms. When it does, these symptoms are very diverse and range from flu-like symptoms, such as fever and sore throat, to breathing difficulty and muscle weakness leading to paralysis. The severity of symptoms depends on the body site involved, especially the brain or spinal cord (central nervous system). Fortunately, in approximately 90% of cases, the central nervous system is not involved. Without nervous system involvement, there is a 90% expected rate of full recovery (Source: PubMed).

Polio is a very serious infection, especially when the central nervous system (brain and spinal cord) is affected. Pay close attention to symptoms that suggest involvement of the nervous system, which can result in paralysis or may be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have the following symptoms, including difficulty breathing, swallowing, or urinating; fever for five or more days; sudden muscle weakness or weakness limited to one side of the body; muscle pain, contractions, or spasms; or stiff neck and back.

What are the symptoms of polio?

Symptoms of polio are generally categorized by the three patterns of infections that develop. These include subclinical infections, nonparalytic infections, and paralytic infections. Most people (about 95%) infected with the polio virus will not have any symptoms, although when symptoms do occur, they can be serious (Source: CDC).

Subclinical symptoms of polio

Subclinical infections may not produce symptoms at all. If symptoms do appear, they tend to be mild and resolve within 72 hours. These symptoms are also commonly seen with other, more common diseases, so they may not be recognized as symptoms of polio. Symptoms of subclinical infection include:

Nonparalytic symptoms of polio

Subclinical symptoms of polio can progress to nonparalytic symptoms, which do not cause paralysis but are serious. Nonparalytic symptoms of polio include:

Paralytic symptoms of polio

Paralytic symptoms are very serious and have the potential to cause paralysis. Paralytic symptoms of polio include:

  • Abdominal bloating and constipation

  • Difficult or painful urination

  • Difficulty breathing

  • Drooling

  • Extreme sensitivity to touch

  • Fever five to seven days before other symptoms begin

  • Headache

  • Irritability or poor temper control

  • Muscle contractions, pain or spasms

  • Muscle weakness limited to one side of the body (asymmetrical), which may progress to paralysis

  • Stiff neck and back

Serious symptoms that might indicate a life-threatening condition

In some cases, polio can be life threatening, especially when the central nervous system (brain and spinal cord) is affected. Pay close attention to symptoms that suggest involvement of the nervous system, as this could result in paralysis or permanent complications. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

What causes polio?

Polio is a viral infection. Transmission occurs through direct person-to-person contact or through mucus, saliva or feces.

In some cases, the virus remains in the intestines, causing only mild, subclinical symptoms. If it circulates through the bloodstream and lymphatic system, it can involve the nervous system and potentially lead to long-term complications.

Both oral and inactivated polio vaccines (OPV and IPV, respectively) are available to protect against the polio virus. The IPV is part of the routine recommended immunization schedule for children in the United States. The IPV is given in injection (shot) form.

What are the risk factors for polio?

A number of factors increase the risk of developing polio. Not all people with risk factors will get polio. Risk factors for polio include:

  • Exposure to an infected person if you have not been vaccinated

  • No prior immunization with the polio vaccine

  • Poverty

  • Travel to a region where polio is common if you have not been vaccinated

  • Unsanitary living conditions

Reducing your risk of polio

Vaccines have mostly eliminated polio in the Western world. If you have not been vaccinated, you may be at increased risk for polio, especially if you travel to other countries where the infection still exists.

You may be able to lower your risk of polio through the following steps:

  • Avoiding contact with an infected person if you have not been vaccinated

  • Receiving the polio vaccine

How is polio treated?

Treatment for polio begins with seeking medical care from your health care provider. If you show signs or symptoms of polio, your health care provider may run tests on your spinal fluid to detect antibodies to the polio virus and perform throat cultures before developing a treatment plan.

Treatments for polio

The goal of treatment is to control your symptoms, and the plan may involve a combination of medication, physical therapy, and self-care measures. It is important to follow the treatment your health care provider has prescribed, which may include:

What are the potential complications of polio?

The long-term effects of polio depend on the parts of your body that are involved, and nonparalytic and paralytic infections are associated with a higher risk of complications compared with the subclinical form. Overall, less than 1% of infections results in paralysis.  http://www.cdc.gov/vaccines/vpd-vac/polio/in-short-both.htm#vacc

You can help minimize your risk of serious complications by following the treatment plan that you and your health care professional design specifically for you. Complications of polio can include:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 18
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Poliomyelitis. PubMed Health, a service of the NLM from the NIH. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002375/
  2. Vaccines and immunizations: polio disease in-short. Centers for Disease Control and Prevention. http://www.cdc.gov/vaccines/vpd-vac/polio/in-short-both.htm
  3. Centers for Disease Control and Prevention (CDC). Tracking progress toward global polio eradication, 2010-2011. MMWR Morb Mortal Wkly Rep 2012; 61:265.