What is the recommended Haemophilus influenzae type b (Hib) vaccination schedule?

Haemophilus influenzae type b (Hib) Vaccination Schedule

The Advisory Committee on Immunization Practices (ACIP) recommends routine administration of Hib conjugate vaccine beginning at age 2 months, with either a 2-dose primary series (PRP-OMP vaccines) or 3-dose primary series (PRP-T vaccines), followed by a booster dose at 12-15 months of age. 1

Routine Vaccination Schedule

Primary Series Options:

• PRP-OMP vaccines (PedvaxHIB or Comvax):

  • 2 doses at 2 and 4 months
  • Preferred for American Indian/Alaska Native infants due to substantial protection after first dose 2

• PRP-T vaccines (ActHib, Pentacel, MenHibRix):

  • 3 doses at 2,4, and 6 months

Booster Dose:

• All children should receive a booster dose at 12-15 months
• Any licensed Hib conjugate vaccine can be used for the booster, regardless of what was used for the primary series
• Booster should be given at least 8 weeks after the most recent Hib vaccination 1, 3

Important Administration Guidelines

• Doses in the primary series should ideally be administered 8 weeks apart
• If necessary, a minimum interval of 4 weeks between doses is acceptable
• First dose can be administered as early as 6 weeks of age 1, 3
• If PRP-OMP vaccine is not used for both primary doses or there's uncertainty about previous products used, a third primary dose is needed 1
• Hiberix should only be used for the booster dose in children 12 months through 4 years who have received at least 1 previous Hib dose 1

Catch-up Vaccination Schedule

For children with delayed vaccination:

• First dose at <7 months:

  • 2 doses of PRP-OMP or 3 doses of PRP-T with minimum 4-week intervals
  • Booster at 12-15 months (only if primary doses given before 12 months)

• First dose at 7-11 months:

  • Second dose at least 4 weeks later
  • Final dose at 12-15 months or 8 weeks after second dose (whichever is later)

• First dose at 12-14 months:

  • Second dose 8 weeks after first dose
  • No third dose needed

• First dose at 15-59 months:

  • Single dose only, no additional doses needed 1, 3

Special Populations

For children at increased risk for invasive Hib disease (asplenia, HIV, immunodeficiency, etc.):

• <12 months: Follow routine recommendations

• 12-59 months:

  • If unimmunized or received 0-1 dose before 12 months: 2 doses, 8 weeks apart
  • If received ≥2 doses before 12 months: 1 dose 8 weeks after last dose
  • If completed primary series and received booster ≥12 months: no additional doses

• Chemotherapy/radiation therapy patients <60 months:

  • If routine doses given ≥14 days before therapy: no revaccination needed
  • If dose given <14 days before or during therapy: repeat doses ≥3 months after therapy completion

• Hematopoietic stem cell transplant recipients (all ages):

  • 3 doses (≥4 weeks apart) beginning 6-12 months after transplant 1

Common Pitfalls and Caveats

1. Vaccine type confusion: Don't confuse PRP-OMP with PRP-T vaccines, as they have different primary series requirements (2 vs. 3 doses) 3

2. Combination vaccines: Be aware that Hib is available in several combination vaccines:

   • Comvax (Hib-HepB)
   • Pentacel (DTaP-IPV-Hib)
   • MenHibRix (Hib-MenCY)
   • Vaxelis (DTaP-IPV-Hib-HepB) - preferred for AI/AN infants due to PRP-OMP component 2

3. Vaccine shortages: During shortages, prioritize the primary series for all children and defer booster doses for children not at high risk for disease 4

4. Special populations: Pay special attention to high-risk groups who may need additional doses or modified schedules 1

5. Documentation: Clearly document which Hib vaccine product is used to ensure proper completion of the primary series 1, 3