Pediarix Vaccine: Questions and Answers

Clinical Questions and Answers

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Pediarix™ is a combination product containing DTaP, hepatitis B, and inactivated polio vaccines. It is produced by GlaxoSmithKline, and was licensed on December 13, 2002.

General Questions

Who is eligible to get Pediarix?

Pediarix is approved as a 3-dose primary series, at 2, 4, and 6 months of ages. It is licensed for children 6 weeks through 6 years of age.

Who should NOT get Pediarix?

Pediarix should not be given to infants less than 6 weeks of age or to anyone 7 years of age or older. (Also see “Contraindications,” below.)

Can providers use Pediarix for booster doses of DTaP and IPV after the 3-dose primary series?

No. Pediarix is licensed only for the primary series. It should be followed with 4th and 5th doses of DTaP and a 4th dose of IPV at appropriate ages.

Are the individual components of Pediarix identical to vaccines already available in the U.S.?

Pediarix contains the same DTaP and hepatitis B antigens used in existing U.S. vaccines (Infanrix and Engerix-B, respectively). The IPV component is derived from a vaccine that has been used in other countries since 1996. It has not been used previously in the U.S., but contains the same three poliovirus types, strains, and antigen content as the currently-licensed U.S. vaccine.

Is Pediarix as immunogenic as the three component vaccines given separately?

Yes. Clinical studies have shown the immune response to Pediarix to be comparable to that of the separate vaccines.

Is the hepatitis B immune response to Pediarix given at 2, 4, and 6 months comparable to that of monovalent hepatitis B vaccine given at birth, 1 month and 6 months?

Yes. The concentration of antibody to hepatitis B surface antigen is higher in groups of children given monovalent hepatitis B vaccine at birth, 1 and 6 months, but the percentage of children achieving protective antibody titers is the same.

Vaccine Use, Recommendations & Schedule

If a child gets a birth dose of monovalent hepatitis B vaccine, can he/she get Pediarix for subsequent doses?


Can a child who received a birth dose of monovalent hepatitis B vaccine still receive a 3-dose series of Pediarix, even though this would mean getting an extra dose of hepatitis B?

Yes. The additional dose of hepatitis B vaccine is acceptable, and the child will be getting one less injection overall.

Are CDC and AAP relaxing their recommendations regarding the birth dose of hepatitis B vaccine to encourage parents to use Pediarix?

No. CDC and AAP still encourage parents to get their children the first dose of hepatitis B vaccine at birth.

May an infant born to a HBsAg-positive mother or a mother whose HBsAg status is unknown be given Pediarix after a birth dose of monovalent hepatitis B vaccine?

Yes. The ACIP has approved the use of Pediarix to complete the series regardless of the mother’s HBsAg status.

Why does CDC recommend Pediarix for infants of HBsAg positive mothers or mothers whose HBsAg status is unknown when the FDA did not license the vaccine for these children?

The Advisory Committee on Immunization Practices is constituted by the Department of Health and Human Services to make recommendations about the appropriate use of vaccines and other biologic products in the United States. Before making these recommendations, the Committee examines all available data on the topic. There are times when the data clearly support the use of a vaccine in a manner not specifically approved by the FDA. The reason for this is that the FDA requires specific data, in the form of a clinical trial, to support each licensed indication.

Neither Merck (Comvax) nor GSK (Pediarix) have tested their combination vaccines in a blinded manner among infants born to HBsAg positive women. However, the data are very clear that the response to the hepatitis B component of the combinations is at least as good, and may be better, than the response to the vaccine given alone. There is no biologic evidence or reason to believe that infants born to HBsAg positive women respond any differently to hepatitis B vaccine (alone or in combination) than infants born to HBsAg negative women. This is not experimentation. This is rational extrapolation of established vaccine response data. If there were any reason whatsoever to believe that the response to hepatitis B vaccine in a combination was different in these children than to monovalent vaccine, ACIP would not have made the recommendation they made.

May Pediarix be given simultaneously with other vaccines?

Yes. Pediarix may be given with any other vaccines at separate injection sites.

Does use of Pediarix affect the total number of doses required of the three component vaccines?

No. Boosters of DTaP and IPV are still required at the usual ages using vaccines other than Pediarix. A 3-dose series of Pediarix satisfies the requirement for hepatitis B vaccine.

What are the minimum intervals and minimum ages for each dose of Pediarix?

The minimum age and interval for each dose are equivalent to the longest interval or oldest age recommended for any of the individual components for that dose. (For example, the minimum age for dose 1 is 6 weeks, the same as DTaP and IPV, while the minimum age for dose 3 is 6 months, the same as hepatitis B.)

Minimum Interval From Previous Dose
Dose Minimum Age Minimum Interval From Previous Dose
1 6 weeks N/A
2 10 weeks 4 weeks
3 6 months 8 weeks *

*And 16 weeks from Dose 1

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Can Pediarix be used to complete a primary series begun with individual DTaP, hepatitis B and IPV vaccines?

Yes, if the child received Infanrix as the DTaP vaccine. It is preferable to use the same manufacturer’s DTaP vaccine for all doses in the primary series. But if you do not know whether a child received Infanrix for prior doses, or if Pediarix is the only DTaP-containing vaccine available, Pediarix may still be used to complete the series.

Can a child who starts the series with Pediarix switch to individual DTaP, hepatitis B and IPV vaccines?


Can a child who has received one or more doses of DTaP from another manufacturer complete the primary series with Pediarix, or can a child who began the series with Pediarix switch to another manufacturer’s DTaP?

Whenever feasible, the same brand of DTaP should be used for all doses of the primary series. However, if this isn’t possible, use a different manufacturer’s product rather than defer vaccination.

May Pediarix be used to complete a primary series begun using other manufacturers’ IPV or hepatitis B vaccines (or vice versa)?


If a dose of Pediarix is inadvertently administered at less than 6 weeks of age, should it be repeated at the appropriate age?

The DTaP and IPV components should be repeated. The hepatitis B component need not be repeated.

If a dose of Pediarix is inadvertently given to a patient 7 years of age or older, would the DTaP component count as a dose of Tdap, or would it have to be repeated?

In this situation count the DTaP dose as if it were Tdap. Do not repeat.

If Pediarix is inadvertently given as a 4th dose or school booster (4-6 years), may it be counted, or should any of the vaccines be repeated?

As long as the dose was given at an age and intervals appropriate for the individual components it does not need to be repeated.

May COMVAX be used after Pediarix has been used for one or more doses of hepatitis B vaccine; or may Pediarix be used after COMVAX has been used for one or more doses?

Yes. Either use is acceptable.

May Pediarix be used as part of an accelerated DTaP schedule (e.g., during a pertussis outbreak) when the third dose is given at under 6 months of age or less than 8 weeks after dose two?

Pediarix may be used to begin such an accelerated schedule, using the minimum interval of 4 weeks between doses 1 and 2. DTaP, rather than Pediarix, would normally be recommended for the third dose in this situation. However, Pediarix may be used as long as an additional dose of hepatitis B vaccine is given at the appropriate age and interval to ensure proper boosting.

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Safety and Contraindications

Is the safety profile of Pediarix similar to that of the three component vaccines?

Overall the rates of other adverse events were comparable in clinical trials, although infants who received Pediarix had somewhat higher rates of fever >100.4°F than infants who received the component vaccines injected at separate sites.

Is it safe to give Pediarix with Hib and PCV at the same visit?

These vaccines may be given at the same visit. However, safety information is not yet available for all doses in the primary series when Pediarix, Hib and PCV are given at the same visit. After the first dose of Pediarix with Hib and PCV, the rate of fever >100.4°F was higher than when hepatitis B vaccine (Engerix™), DTaP (Infanrix™), Hib, and PCV were administered separately at the same visit.

Does Pediarix contain thimerosal?

Pediarix does not contain thimerosal as a preservative. Thimerosal is used during the early stages of production, and subsequently removed, leaving only a clinically insignificant trace.

What conditions contraindicate Pediarix?
  1. Hypersensitivity to any component of the vaccine, including yeast, neomycin, and polymyxin B.
  2. A history of anaphylaxis after a previous dose of Pediarix or any of its components.
  3. A history of encephalopathy within 7 days of a previous dose of any pertussis-containing vaccine.
  4. Progressive neurologic disorder, including infantile spasms, uncontrolled epilepsy, or progressive encephalopathy.
Are there other warnings or precautions regarding the use of Pediarix?

Warnings and precautions for the individual components also apply to Pediarix. Conditions for which Pediarix, or one of its components, should be deferred, or the risks weighed against the benefits include: temperature of >105°F within 48 hours of a prior dose, collapse or shock-like state within 48 hours of a prior dose, persistent inconsolable crying for 3 or more hours occurring within 48 hours of a prior dose, seizures with or without fever within 3 days of a prior dose, Guillain-Barré syndrome within 6 weeks of a prior dose, or concurrent moderate or severe acute illness. Immunosuppressive therapies may reduce the immune response to the vaccine. See the package insert for details.

Can Pediarix be given to children with HIV infection?


Can children with latex allergies get Pediarix?

While the vial stopper is latex-free, the tip cap and rubber plunger of the needleless prefilled syringes contain dry natural latex. This may cause an allergic reaction in a child with a severe latex allergy.

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Administration, Storage and Handling

What are the recommended route and site for administering Pediarix?

Pediarix should be given intramuscularly, using a 7/8-1 inch, 22-25 gauge needle. The anterolateral thigh is the preferred site, although the deltoid is acceptable when there is adequate muscle mass.

How should Pediarix be stored?

Pediarix should be refrigerated between 36° and 46°F (2° and 8°C).

May Pediarix be frozen?

No. Pediarix that has been subjected to freezing temperatures should be discarded.

How is Pediarix supplied?

Pediarix is supplied in single-dose vials; and pre-filled disposable syringes, with or without needles.

Programmatic Issues

Is Pediarix available through VFC?


How do I record administration of Pediarix on a shot record that doesn’t have spot designated for it?

Record the date under each separate component.

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