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Understanding polio

Though polio has been all but eradicated in the United States, it is still present in other countries. It pays to protect yourself and your children with an immunization.

Nobody likes needles, but polio shots still beat facing the virus unarmed.

Before polio vaccine, epidemics struck American cities regularly. Thousands of people were sickened, paralyzed and killed. Most of them were children.

The poliovirus enters the body by mouth and multiplies in the intestines. About 95% of people who get infected with poliovirus don't have any symptoms, according to the Immunization Action Coalition. Those who do have symptoms may have a fever, fatigue, headache, vomiting, neck stiffness and pain in the limbs, according to the World Health Organization.

If the virus enters the bloodstream, it can attack the central nervous system. This can cause muscle pain, fever, paralysis, brain inflammation and difficulty breathing.

Paralysis from polio is almost always permanent. If the virus paralyzes the lungs or attacks the brain, it can be fatal.

According to the American Academy of Pediatrics and the American Academy of Family Physicians, all children should receive four doses of inactivated polio vaccine (IPV) at the ages of 2 months, 4 months, 6 to 18 months and 4 to 6 years.

IPV is given as a shot and contains dead poliovirus that can't infect the body. It "teaches" the body to recognize poliovirus so that if live virus enters the body the immune system is ready to attack it.

Doctors used to recommend oral polio vaccine (OPV) and IPV on an alternating schedule. OPV uses a living but weakened strain of poliovirus.

Because the virus in OPV is still alive, it still grows in the intestines but isn't usually strong enough to invade the body. OPV isn't recommended anymore in the United States because, in rare cases, it can cause polio and paralysis.

OPV remains the treatment of choice in some nations where the price and difficulty of using sterile needles for IPV makes it impractical. Also, because the virus grows in the intestines after taking OPV, the virus shed in the stool can help to immunize the people in close contact with the immunized person.

Although the Western Hemisphere was declared free of poliovirus in 1994, many experts believe we're still vulnerable. As long as polio exists anywhere, they assert, it can travel into the United States.

For more information on poliovirus and polio vaccine, visit the websites of the Centers for Disease Control and Prevention, World Health Organization or UNICEF.

Reviewed 5/1/2023

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