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Vaccines and Preventable Diseases:

Polio Vaccine - Submitted Q&A
Questions submitted during immunization satellite broadcasts or through NIPINFO

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Clinical questions on this page:

General Questions

Can IPV be given in the arm before one year of age?

Yes. IPV can be given by the intramuscular (IM) or subcutaneous (subQ) route. It can be given by the subQ route into the upper-outer triceps area of an infant, if necessary. This can be especially helpful to remember when you're giving multiple vaccines in any one visit. ACIP General Recommendations Adobe Acrobat print-friendly PDF file (see page 12) (2/20/03)

What is the relation of the SV40 virus to Polio vaccine? We hear about this in the media sometimes.

SV40 is a virus found in some species of monkey. Soon after its discovery in 1960, SV40 was found in polio vaccine.

More than 98 million Americans received one or more doses of polio vaccine during the period 1955-1963, when some of the vaccine was contaminated with SV40. SV40 has been found in certain types of human cancers, but it has not been determined that SV40 causes these cancers. The majority of evidence suggests that it does not, but some research results are conflicting and more studies are needed. For further information, please visit this website: NIP SV40 Webpage. (2/20/03)

Why does the graph depicting incidence of polio flatten out prior to the introduction of OPV and not after?

Millions of doses of IPV were administered when the vaccine was licensed, leading to a tremendous decline in polio infections. The subsequent introduction of OPV sustained this decline and led to the eventual eradication of wild polio virus transmission in the United States and many other parts of the world. Pink Book Chapter: Poliomyelitis Adobe Acrobat print-friendly PDF file (see page 74) (2/20/03)

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Are there any circumstances when a fifth dose of polio vaccine is recommended?

Yes. If upon record review you find that a dose was given before the minimum age of 6 weeks or if any doses were given before the minimum interval of 4 weeks, then you may need to repeat an invalid dose. Also, if all 4 doses are given before 4 years of age and school law requires a dose after age four, you may have to give a 5th dose. Finally, adults who completed their series as children and are traveling to a polio endemic area may receive a single lifetime booster dose of IPV. ACIP Polio Recommendations Adobe Acrobat print-friendly PDF file (see page 13) (2/20/03)

If 3 doses of IPV confers 99% immunity and we only give adults a 3-dose series, why is it necessary to give children a 4-dose series? This sometimes means that we have to give a 5th or 6th dose if the 4th dose was given before the 4th birthday.

To some extent this is a phenomenon that is driven by a state’s immunization requirements. It’s really a case of hedging the bet in case the child did not develop antibodies to the 2-month-old dose. Maternal antibodies don’t have much impact on inactivated vaccines, but they may reduce the immune response by a little. Giving 4 doses is a conservative approach. (2/20/03)

We see children, especially immigrants, who have received multiple doses (up to 6-8 doses total) of OPV. If they have more than 4 doses of OPV given before age 4, is it necessary to give an additional dose of IPV after age 4.

ACIP recommends that the 4th dose in the polio series should be given at the time a child enters kindergarten or first grade (4-6 years of age). But if the child has received a total of four doses of any combination of OPV or IPV at least 4 weeks apart, the child does not need a fifth dose at school entry. Some states' school entry regulations require at least one dose of polio vaccine to be given on or after the fourth birthday, regardless of the number of doses given before the fourth birthday. ACIP Polio Recommendations Adobe Acrobat print-friendly PDF file (see page 12-13) (2/30/03) More Information

What is the IPV schedule for a child 7 years of age or older with no immunization record.

In this situation the catch-up schedule should be used. The child will need 3 doses of IPV with each dose separated by 4 weeks. ACIP Pediatric Catch-up Schedule (see page 3) (2/20/03)

A 12-year-old child received OPV #1 in 11/90, OPV #2 in 11/91, and IPV on 3/05/03. Is the polio series complete or does this child need another dose of polio?

This child needs one more dose of IPV. Whenever OPV and IPV are used in the same series, a complete series is 4 total doses, even if those doses are spread over several years. If the child had received all OPV or all IPV and a dose was given after age 4, we would not recommend an additional dose unless the person were going to travel to a polio endemic area. ACIP Polio Recommendations Adobe Acrobat print-friendly PDF file (see pages 12-14) (2/20/03)

If dose one in the vaccination series is Pediarix (DTaP, IPV, Hepatitis B) and the second dose in the series is separate DTaP, IPV, and Hepatitis B vaccines, does the IPV count since it is a different IPV than the one in the combined Pediarix vaccine?

Yes, all doses in the combined vaccine and the separate vaccines can be counted as valid doses as long as none of the doses violate minimum age and minimum interval guidelines. These vaccines are all licensed by FDA. (2/20/03)

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Why do we immunize people in other countries with OPV? The hygiene is so much worse and the living conditions are poor. Why are we not using IPV?

There are several reasons. OPV is cheaper and easier to administer than IPV. The shedding of the virus in the stool to contacts is beneficial in an area where the disease is endemic or has recently been endemic because it enhances herd immunity. Current supplies of IPV are also inadequate to meet the needs of polio eradication efforts in other countries. As combination vaccines including IPV become available in other countries and the risk of vaccine associated paralytic polio (VAPP) begins to outweigh the risk of wild polio virus infection, especially in countries with high rates of HIV, OPV will very likely be replaced with IPV. (2/20/03)

If a child developed polio after OPV vaccine, does the child, who is now a teenager, need the IPV vaccine?

Yes. The child is only immune to the strain of polio with which he was infected. There are 3 strains of polio virus in both OPV and IPV. The child still needs protection against the other two strains of polio. He should receive 3 doses of IPV, inactivated polio vaccine. The minimum interval between all doses is 4 weeks. (2/20/03)

What is the incidence of vaccine associated paralytic polio (VAPP) in the developing world?

The overall risk of VAPP in developing countries has been estimated to fall in the range of 1 case per 1.5 million doses administered (Latin America) to 1 case per 4.6 million doses administered (India). These are the only two developing countries/regions with published studies on this topic. Work is currently in progress to estimate risk of VAPP per million birth cohort, which will provide numbers that are potentially more useful to policy-makers in the future. (2/20/03) More Information

Since Type II Polio has been eradicated, will they be changing the composition of OPV. It seems that if the Type II was taken out, then polio could be eradiated in about 30% less time with 30% fewer resources. I know getting a new vaccine approved in the USA is quite a process, but could it be done cheaper and more quickly in another country?

There is no OPV vaccine of any type licensed or used in the U.S. now. There has been some discussion about monovalent and bivalent vaccines as part of the end-game strategy but this is just in the discussion phase right now. (8/21/03)

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Additional Information

Multiple OPV

The reason you find children from other countries with multiple doses of polio vaccine isn’t because they don’t know what they are doing. You are witnessing the polio eradication program in action. They basically vaccinate every child in the entire country who is five years of age or younger on the same day. They do this for several cycles on two immunization days each year. Therefore, you are going to see kids with 4, 5, 6, or more polio doses.

Incidence of VAPP

There has not been a lot of research on this question in developing countries. Citations for two published studies are given below. VAPP risk is estimated in terms of number of VAPP cases per OPV doses distributed, per first OPV dose distributed, or per birth cohort. Some studies have also tried to separate out “recipient VAPP” (that occurring among persons who have documented receipt of OPV) and “contact VAPP” (occurring among persons without direct receipt of OPV, but assumed to have resulted due to contact with another person who received OPV). All of these numbers are estimates; there are challenges inherent in the methodologies used to come up with these estimates that would require reading the original papers to understand strengths and weaknesses.

Published Studies:

Kohler KA, Banerjee K, Hlady WG, Andrus JK, Sutter RW. Vaccine-associated paralytic poliomyelitis in India during 1999: decreased risk despite massive use of oral polio vaccine. Bull WHO 2002;80:210-6.

Andrus JK, Strebel PM, de Quadros CA, Olive JM. Risk of vaccine-associated paralytic poliomyelitis in Latin America, 1989-91. Bull WHO 1995;73:33-40.


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This page last modified on April 22, 2004
Content last reviewed on April 22, 2004
Content Source: National Center for Immunization and Respiratory Diseases

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