Oral Polio Vaccine

What is polio?

Polio is a disease caused by a virus. It enters a child’s (or adult’s) body through the mouth. Sometimes it does not cause serious illness. But sometimes it causes paralysis (can’t move arm or leg). It can kill people who get it, usually by paralyzing the muscles that help them breathe. Polio used to be very common in the United States. It paralyzed and killed thousands of people a year before we had a vaccine for it.

Why get vaccinated?

Polio Vaccine can prevent polio.

History: A 1916 polio epidemic in the United States killed 6,000 people and paralyzed 27,000 more. In the early 1950ís there were more than 20,000 cases of polio each year. Polio vaccination was begun in 1955. By 1960 the number of cases had dropped to about 3,000, and by 1979 there were only about 10. The success of polio vaccination in the U.S. and other countries has sparked a world-wide effort to eliminate polio.

Today: No wild polio has been reported in the United States for over 20 years. But the disease is still common in some parts of the world. It would only take one case of polio from another country to bring the disease back if we were not protected by vaccine. If the effort to eliminate the disease from the world is successful, some day we won’t need polio vaccine. Until then, we need to keep getting our children vaccinated.

Two types of polio vaccine

There are two types of polio vaccine:

  • IPV (Inactivated Polio Vaccine): A shot. IPV is the recommended polio vaccine for almost everyone in the United States.
  • OPV (Oral Polio Vaccine): Drops, by mouth.

Until recently, OPV was recommended for most children in the United States. But it is no longer recommended except in limited circumstances. OPV helped us rid the country of polio, and it is still used in many parts of the world. Both vaccines give immunity to polio, but OPV is better at keeping the disease from spreading to other people. However, for a few people (about one in 2.4 million), OPV actually causes polio. Since the risk of getting polio in this country is now extremely low, experts believe that using oral vaccine is no longer worth the slight risk. The polio shot we now use (IPV) does not cause polio. This article is about Oral Polio Vaccine (OPV). Your health care provider should also give you a Vaccine Information Statement for Inactivated Polio Vaccine (IPV).

Who should get OPV and when?

OPV is no longer recommended for routine use in the United States. It should be used only in certain circumstances:

  1. Mass immunization campaigns to control polio outbreaks;
  2. Children who have never gotten any polio vaccine who plan to travel within 4 weeks to countries where polio is common. These children may get OPV for the first dose;
  3. Children whose parents do not accept the recommended number of injections. These children should get IPV for the first two doses of the polio vaccine series, but may get OPV for the third or fourth dose, or both;
  4. People with a life-threatening allergy to the antibiotics neomycin, streptomycin, or polymyxin B, or people who have had a life-threatening allergic reaction to a dose of IPV. These people may get OPV instead.

If you or your child is in one of these 4 groups, ask your health care provider when the vaccine should be given. Also ask about the risks of vaccine-associated polio before getting OPV. OPV may be given at the same time as other vaccines.

Some people should not get OPV or should wait.

These people should not get OPV:

  • Anyone who is taking long-term steroids or any other drug that affects the immune system.
  • Anyone who has cancer or is getting chemotherapy.
  • Anyone who has AIDS or HIV infection, or another disease that affects the immune system.
  • If anyone in these three groups will be changing a child’s diapers or be in close contact with a child getting polio vaccine, that child should not get OPV.
  • A baby should not get OPV if someone who will be in close contact with the baby (for instance changing diapers) has never had any kind of polio vaccine.
  • Anyone who has had a severe allergic reaction to a dose of OPV should not get another dose.

These people should wait:

  • Anyone who is moderately or severely ill at the time the immunization is scheduled should usually wait until they recover before getting OPV. People with minor illnesses, such as a cold, may be vaccinated.

What are the risks from oral polio vaccine?

OPV can, rarely, actually cause polio. This is why it is no longer recommended for most people. It caused several cases of polio each year (about 1 case for every 2.4 million doses of vaccine) during the years it was used. OPV can cause polio in people who get the vaccine or in people who are in close contact with them. Today, with polio under control in the U.S., experts believe IPV can protect children and adults just as well, without the risk. A vaccine, like any medicine, could cause other serious problems, such as a severe allergic reaction. The risk of OPV causing serious harm, or death, is extremely small.

What if there is a serious reaction?

What should I look for?

  • Look for any unusual condition, such as a serious allergic reaction, high fever, unusual behavior, or signs of paralysis. If a serious allergic reaction occurred, it would happen within a few minutes to a few hours after the shot.
  • Signs of a serious allergic reaction can include:
    • difficulty breathing
    • weakness
    • hoarseness or wheezing
    • a fast heart beat
    • hives
    • dizziness
    • paleness
    • swelling of the throat.

If paralysis were to occur, it could happen from about a week to about a month after the vaccination. Symptoms might include:

  • severe muscle aches and spasms
  • weakness
  • loss of movement in an arm or leg

What should I do?

  • If you think it is a severe allergic reaction or other emergency that can’t wait, call your local emergency service or get the person to the nearest hospital. Otherwise, call your doctor.


Adapted from Immunization Action Coalition, Vaccine Information Statements