Inactivated Polio Vaccine (IPV)

Written by Mary Anne Dunkin, Hallie Levine
Medically Reviewed by Jabeen Begum, MD on February 20, 2025
8 min read

The polio vaccine or shot helps stop the spread of polio. The U.S. uses the inactivated polio vaccine (IPV). It's one of two types of polio vaccinations to prevent infection.

Polio is a virus that can cause a serious infection. It can infect your throat, intestines, and nervous system within hours. The virus can also lead to chronic paralysis, too. Polio spreads through an infected person's stool (poop) or in droplets containing the virus (cough or sneeze). 

If you get symptoms, they can start as a fever, fatigue, or headache. You may also have neck stiffness, limb pain, or vomiting. Polio can cause permanent paralysis in about 1 in 200 people. And of those people, about 1 in 10 may die from the infection. 

What does inactive polio vaccine mean?

Inactivated polio vaccine (IPV) is made from an inactive or killed virus. That means it can’t infect you. Kids in the U.S. get the IPV shot. So your child's overall risk of getting polio from the vaccine is very low. 

There’s another form of the vaccine called the oral poliovirus vaccine (OPV). It contains weakened virus. OPV is used in other countries where the risk of polio is high. It's easier to give to a lot of people. But the U.S. doesn't use this oral form because it's made with live virus. 

 

 

If you haven't heard much about polio, you may wonder why children need a polio vaccine. Polio was once the leading cause of disability in the U.S. In the 1940s, the polio virus paralyzed around 20,000 people each year.

When the American scientist Jonas Salk made the first polio vaccine, it protected people from polio infection. By the late 1950s, regular vaccinations were underway. The clinical trials showed the polio shot worked. It help prevent polio infection, too. So parents brought their children to wait in long lines for hours to get it. Now, it's almost gone since the first vaccine started protecting people in 1955.

Most people with polio don’t get symptoms. They might not feel the flu-like signs, such as fever, sore throat, headache, stomach upset, or nausea. But more rarely, polio can spread to your brain and spinal cord. It can cause serious symptoms:

  • Meningitis is an infection of the membrane covering your spinal cord and brain. This can affect up to 5 in 100 people with polio.
  • About 1 in 200 people with polio can get paralysis. And around 1 in 10 may die from respiratory failure --- the virus stops your breathing muscles.

A little less than half of people who have polio can also get a health condition called post-polio syndrome (PPS). It starts 15 to 40 years after polio infection. PPS can cause muscle weakness, fatigue, and joint pain.

The last case of polio in the U.S. was in 1979. But polio is still common in some developing countries. The infection can spread when people travel. The vaccine can prevent serious, life-threatening infections. In 2022, an unvaccinated U.S. citizen caught polio while traveling. They got polio in another country and became permanently paralyzed.

If you got the polio shot before 2000, you probably got the oral polio vaccine (OPV). OPV was made from a live poliovirus. OPV was first used because it was fairly cheap. OPV was also easy to give to people as drops on the tongue. But very rarely — about 1 in 2.7 million OPV doses — the virus can spread from the gastrointestinal (GI) tract to the spinal cord, where it causes paralysis. 

To be safe, the U.S. switched to the inactive polio vaccine (IPV) in 2000. And IPV protects you like OPV, without the risk of paralysis. Your child will get IPV as a shot in the arm or leg at the doctor's office.

Most people get vaccinated for polio as children in the U.S. And some schools may require the polio shot before your child starts school. Children should get four doses of IPV at the following ages:

  • 2 months
  • 4 months
  • 6-18 months
  • A booster dose at 4-6 years

IPV may be given at the same time as other vaccinations.

Routine polio shots aren't done for people aged 18 or older who live in the U.S. Most people are already vaccinated. But three groups of adults have higher risk for polio infection. You may want to consider IPV if you're not vaccinated and are:

  • Traveling to other parts of the world where polio is still common.
  • Working in a lab that handles specimens that may contain polioviruses.
  • A health care worker who has close contact with people who could be infected with the poliovirus.

If you fall into any of these groups, talk to your doctor about the polio shot. If you decide to get vaccinated, you'll get three doses of IPV:

  • The first dose at any time.
  • The second dose 1 to 2 months later.
  • The third dose 6 to 12 months after the second.

If you've already had one or two IPV doses, you'll get the remaining one or two doses. It doesn't matter how long it has been since the earlier IPV vaccine dose or doses.

Just about anyone can safely get the polio vaccine. Always talk to your doctor before getting vaccinated. In very rare cases, the IPV vaccine may not be right for you if you've had a severe allergic reaction called anaphylaxis:

Polio vaccine side effects haven't been reported for pregnant women. But if possible, you should probably avoid it when pregnant, especially if you've had an allergic reaction. Always talk to your doctor before getting any vaccine when pregnant.

If your ill, wait until you feel better before getting a vaccine.

The IPV vaccine is very safe with mild side effects. After the shot, your child may get a sore, red spot where the shot was given, or a fever. 

Your infant or toddler may get irritable, sleepy, or fussy. All of these symptoms usually go away after 48 hours. Here are a few ways you can help them feel better:

  • Apply a cold, damp cloth to their arm to help the red, sore, or swollen spot.
  • Give them a lukewarm sponge bath to cool them down.
  • Offer them liquids often to help them stay hydrated.
  • Ask your pediatrician (baby's doctor) if you can give your child an OTC pain medicine.

The polio vaccine is very effective (prevents polio infection). In almost everyone who gets it, IPV can stop serious infection like meningitis or paralysis. The polio shot can even protect you if you get:

  • Two doses of IPV (at least 90% effective).
  • Three doses of IPV (at least 99% effective).

But if you're immunocompromised (a weakened immune system), the polio vaccine may not work as well. You may not mount a strong response to the IPV vaccine.

That’s one reason for everyone to get the polio shot. If enough people are immune to polio, it's harder for the virus to spread. When you're immune, it means IPV protects you from the potentially life-threatening polio infection.

The polio vaccine can help prevent the spread of a serious viral infection. Without it, polio disease can cause permanent paralysis or even death. The U.S. uses the inactivated polio vaccine (IPV), which is safe and can't infect or paralyze you. It's still important to get your polio vaccine because travelers can still spread the infection.

Has polio been eradicated from the US?

Thanks to the polio vaccine, poliovirus has been eliminated (no longer spreading) from the U.S. But you can still get it if you travel to other countries. In 2022, an unvaccinated U.S. citizen came down with paralytic polio picked up in another country.

Is the polio vaccine necessary?

In the U.S., the polio vaccine is still recommended for everyone. Polio vaccination is the only way to make sure you and your child never get polio. Without it, you could get a serious, life-threatening polio infection.

How long does the polio vaccine last? 

It’s not known for sure, but experts think the vaccine protects you for many years, once you complete the four-shot series. Research shows that most children and adults are protected, even many years later. But if you’re an adult at high risk for polio infection, like traveling to a country with polio, your doctor can give you an IPV booster.

How much does the polio vaccine cost?

Your health insurance usually covers the cost of the polio vaccine. It's usually a preventative service. But it's always a good idea to check with your insurance provider before you go to the doctor. If you don’t have health insurance, your child may be able to get it through the Vaccines for Children (VFC) Program. 

Who discovered the polio vaccine?

A U.S. doctor named Jonas Salk discovered the polio vaccine. He tested a killed-virus vaccine on himself and his family in 1953. Then, he tested it on 1.6 million kids in Canada, Finland, and the U.S. In 1955, polio vaccine use first began the U.S. After two years, there were about 50,000 fewer polio infections. The yearly rate dropped to 5,600 cases by 1957. And the last poliovirus on record in the U.S. was in 1979.