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Centers for Disease Control and Prevention

Vaccines & Immunizations

Vaccines and Preventable Diseases:

Polio Vaccine Questions & Answers
Clinical Questions and Answers

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General Questions

Why did CDC and ACIP change the polio vaccination schedule to an all-IPV series?

The CDC and ACIP changed the polio schedule in 2000 because the only indigenously-acquired polio in the U.S. since 1980 had been due to the oral polio vaccine, while there had been no polio cases due to the wild poliovirus. The ACIP determined that the risk-benefit ratio associated with the exclusive use of the OPV for routine immunization had changed because of the rapid progress in global polio eradication efforts. In particular, the benefits of OPV had diminished in importance due to the elimination of wild virus associated poliomyelitis in the Western Hemisphere since 1991 and the reduced threat of poliovirus importation into the U.S.

Conversely, the risk of vaccine-associated poliomyelitis due to OPV, which caused an average of 8-9 reported cases of paralytic polio each year, was judged less acceptable due to the absence of indigenous disease and reduced risk of imported infection.

Consequently, in 1996 the ACIP and CDC recommended a transition policy to increase use of IPV and decrease use of OPV, and in 2000 recommended exclusive use of IPV.

Isn't IPV less effective than OPV?

No. The IPV that has been used in the U.S. since 1987 is as effective as OPV for preventing polio in the recipient. After two doses of IPV, 90% or more of recipients have protective antibody levels to all types of poliovirus, and after three doses more than 99% have protective antibodies.

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Vaccine handling, storage & injection technique related questions:

Previously, IPV was recommended to be administered subQ only. Now I've read that it may also be given IM. Is this correct?

IPV is approved for either subcutaneous or intramuscular administration.

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Vaccine use, recommendations & schedule related questions:

After what age is routine polio vaccine no longer recommended?

Routine polio vaccination is not recommended for persons 18 years of age and older who reside in the United States.

However, three groups of adult at higher risk for coming into contact with polio virus should consider polio vaccination:

  • Those traveling in polio-endemic or high risk areas of the world. Ask your health care provider for specific information on whether you need to be vaccinated.
  • Those working in a laboratory and handling specimens that might contain polioviruses.
  • Those who are healthcare workers or have close contact with a person who could be infected with poliovirus.


What is the IPV schedule for unvaccinated children 4–18 years of age?

The schedule for routine polio vaccination of children 4–17 years of age is 2 doses of IPV separated by 4–8 weeks, and a third dose 6–12 months after the second dose. If an accelerated schedule is needed, three doses separated by at least 4 weeks may be given. Polio vaccine is not routinely administered to persons 18 years of age and older.

If a child received 4 doses of IPV before the 2nd birthday, with at least 4 weeks between doses, is a 5th dose necessary?

ACIP recommends that the fourth dose in the polio series be given at school entry (4-6 years of age), mainly to assure long-term protection. But a child who has received a total of four doses of polio vaccine at least 4 weeks apart does not need a fifth dose at school entry.

However, some states mandate a dose of polio vaccine to be administered on or after 4 years of age as a requirement for school entry. In this situation just give a fifth dose at school entry. There is no harm in giving an additional dose.

Contraindications, precautions & adverse events related questions:

What is the risk of serious reactions following IPV?

In very rare circumstances, IPV, like any medicine, can cause serious problems, such as a severe allergic reaction. IPV should not be administered to persons who have experienced a severe allergic reaction after a previous dose of IPV or to streptomycin, polymyxin B, and neomycin. The risk of a polio shot causing serious harm, or death, is extremely small.

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This page last modified on April 6, 2007
Content last reviewed on April 6, 2007
Content Source: National Center for Immunization and Respiratory Diseases

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