Haemophilus influenzae type b (Hib) Vaccination: Information for Health Care Providers

FDA categorizes Hib vaccine as a polysaccharide conjugate vaccine, which is a type of inactivated bacterial vaccine. Manufacturers make it by joining a piece of the polysaccharide capsule that surrounds the Hib bacterium to a protein carrier. This joining process is called conjugation. Conjugating a protein carrier to a piece of the polysaccharide capsule from a Hib bacterium creates an effective vaccine. The vaccines use different carrier proteins. All of the vaccines are highly effective against Hib bacteria for people who receive a complete primary series.

Monovalent vaccines

In the United States, FDA licensed 3 monovalent conjugate Hib vaccines. You can use them in infants as young as 6 weeks of age.

• ActHIB^® (PRP-T)
• Hiberix^® (PRP-T)
• PedvaxHIB^® (PRP-OMB)

Combination vaccines

At some ages, a child needs to receive several different recommended vaccines simultaneously. Manufacturers created combination vaccines to decrease the number of injections needed to give these recommended vaccines at the same time. There are 2 licensed combination vaccines that contain Hib vaccine: Pentacel^® and Vaxelis^™.

• Pentacel^® contains lyophilized ActHIB^® that is reconstituted with a liquid DTaP/IPV solution. FDA approved Pentacel^® for all doses of the Hib childhood series (3-dose primary series plus booster dose).
• Vaxelis^™ contains Pentacel^®, except with PedvaxHIB^® for the Hib component, and Recombivax HB^®. FDA approved Vaxelis^™ for doses 1 through 3 of the Hib primary series. It should not be used for the booster dose.

Hib conjugate vaccines are highly effective in producing immunity to Hib bacteria. More than 95% of infants develop protective antibody levels after receiving a primary series of 2 or 3 doses. Invasive Hib disease in a completely vaccinated infant is not common. Although Hib vaccines provide long-lasting immunity, experts do not know the exact duration of immunity.

Hib vaccine is immunogenic in patients with increased risk for invasive disease, including people with:

• Sickle-cell disease
• Leukemia
• HIV infection
• A splenectomy

However, in persons with HIV infection, immunogenicity varies with stage of infection and degree of immunocompromise. Researchers have not performed efficacy studies in populations with increased risk of invasive disease.

Consult the following package inserts for proper storage and handing details, shelf life, and reconstitution instructions:

• ActHIB^®
• Hiberix^®
• PedvaxHIB^®
• Pentacel^®
• Vaxelis™

Store all Hib-containing vaccine refrigerated between 2°C and 8°C (36°F and 46°F).

Do not freeze vaccine or diluents, or expose to freezing temperatures. If the vaccine has been exposed to inappropriate conditions/temperatures or handled improperly:

• Store the vaccine at the appropriate temperature
• Isolate from other vaccines
• Mark "Do NOT Use"
• Consult the vaccine manufacturer and/or your state or local immunization program for guidance

Store Hib vaccine in the original packaging. For Hib vaccines that require reconstitution (Pentacel^®, ActHIB^®, Hiberix^®), the manufacturer packages the diluent and vaccine together. They should be stored together in the refrigerator.

For Hib vaccines that require reconstitution (Pentacel^®, ActHIB^®, Hiberix^®), do NOT use if you cannot resuspend the reconstituted vaccine after thorough agitation.

• Only reconstitute the ActHIB^® in Pentacel^® with the DTaP-IPV liquid provided by the manufacturer.
• Only reconstitute the single-antigen ActHIB^® with the 0.4% sodium chloride provided by the vaccine manufacturer.
• Only reconstitute Hiberix^® with the 0.9% sodium chloride provided by the vaccine manufacturer.
• Never use stock vials of normal saline to reconstitute these vaccines.

Discard vaccine vials and syringes using proper medical waste disposal procedures.

Do not use any Hib vaccine or diluent (if applicable) beyond the expiration date printed on the label.

Prior to administration, visually inspect the vaccine for particulate matter and/or discoloration. If these conditions exist, do NOT use.

Administer all Hib-containing vaccines by the intramuscular route. The preferred injection site in infants and young children is the vastus lateralis muscle of the thigh. The preferred injection site in older children and adults is the deltoid muscle in the upper arm. Use a needle length appropriate for the age and size of the person receiving the vaccine.

All infants, including preterm infants, should receive a primary series of Hib vaccine beginning at 2 months of age. Do not administer Hib vaccine to infants younger than 6 weeks of age because this may induce immunologic tolerance to further doses of Hib vaccine. The number of doses in the primary series depends on the brand of Hib vaccine used:

• If ActHIB^®, Hiberix^®, Pentacel^®, or Vaxelis™ is used, give 3 doses:
  • 1 dose at 2 months of age
  • 1 dose at 4 months of age
  • 1 dose at 6 months of age
• If PedvaxHIB^® is used, give 2 doses:
  • 1 dose at 2 months of age
  • 1 dose at 4 months of age

CDC recommends a booster dose at 12 through 15 months of age for all infants. Vaxelis^™ should not be used for the booster dose. You may use ActHIB^®, Hiberix^®, Pentacel^®, or PedvaxHIB^® for the booster dose.

There are no data on the stability of vaccines stored in syringes filled by healthcare professionals. Therefore, CDC does not recommend predrawing vaccine doses. Do not open vaccine vials until time of administration.

After reconstitution administer:

• ActHIB^® within 24 hours or discard.
• Hiberix^® within 24 hours or discard.
• Pentacel^® immediately (within 30 minutes) or discard.

You can administer a Hib vaccine at the same time as other routine childhood vaccinations. However, administer each vaccine using a separate syringe and, if possible, at a different injection site. Researchers have not observed any clinically significant immune interference from administering Hib vaccines with other routine childhood vaccines during the same visit.