At what age do children receive the Haemophilus influenzae type b (Hib) vaccine?

Hib Vaccination Schedule for Children

Children should begin receiving the Haemophilus influenzae type b (Hib) vaccine at 2 months of age, with the vaccination series able to start as early as 6 weeks of age. 1

Standard Primary Vaccination Schedule

The timing and number of doses depend on which vaccine formulation is used:

For PRP-T Vaccines (ActHib, Hiberix, Pentacel)

• Primary series: 3 doses given at 2,4, and 6 months of age 1, 2
• Booster dose: Single dose at 12-15 months of age (can be given as early as 12 months) 1, 2
• The minimum age for the first dose is 6 weeks 1, 2
• Doses should be spaced at least 2 months apart, though 1 month intervals are acceptable but not optimal 1

For PRP-OMP Vaccines (PedvaxHIB)

• Primary series: 2 doses given at 2 and 4 months of age 1, 3
• Booster dose: Single dose at 12-15 months of age 1
• This formulation is particularly preferred for American Indian and Alaska Native infants due to substantial protection after the first dose 3

For Combination Vaccine (DTaP-IPV-Hib-HepB/Vaxelis)

• Primary series: 3 doses at 2,4, and 6 months of age only 1, 3
• Minimum age for third dose: 24 weeks (due to hepatitis B component) 1
• This vaccine should NOT be used for booster doses 1, 3

Catch-Up Vaccination by Age

For Children 7-11 Months (Previously Unvaccinated)

• HbOC vaccine: 2 doses given at least 2 months apart, plus booster at 15 months 1
• PRP-OMP vaccine: 2 doses given 2 months apart, plus booster at 15 months 1

For Children 12-14 Months (Previously Unvaccinated)

• Single dose before 15 months of age, followed by booster at 15 months (at least 2 months after previous dose) 1

For Children 15-59 Months (Previously Unvaccinated)

• Single dose only - no additional doses needed for healthy children 1, 4
• By age 36 months (3 years), children have developed natural immunity to Hib, making additional catch-up doses unnecessary unless high-risk conditions exist 4

Special Populations Requiring Modified Schedules

High-Risk Children Aged 12-59 Months

Children with the following conditions require additional doses 4:

• Functional or anatomic asplenia (including sickle cell disease)
• HIV infection
• Immunoglobulin deficiency
• Early component complement deficiency
• Receiving chemotherapy or radiation therapy

Dosing for high-risk children:

• If received 0-1 dose before 12 months: Give 2 doses, 8 weeks apart 4
• If received ≥2 doses before 12 months: Give 1 dose, 8 weeks after last dose 4
• If completed primary series plus booster at ≥12 months: No additional doses needed 4

Children ≥60 Months (5 Years and Older)

• Generally do NOT require Hib vaccination unless they have high-risk conditions 4
• High-risk children should receive a single dose of any licensed Hib conjugate vaccine 4
• Hematopoietic stem cell transplant recipients require 3 doses regardless of prior vaccination history 4

Important Clinical Considerations

After Natural Hib Disease

• Children <24 months who develop invasive Hib disease should still receive vaccination, as natural infection at this age does not reliably produce protective immunity 1, 5
• The vaccine series can be initiated or continued at hospital discharge 1

Vaccine Interchangeability

• Ideally, use the same conjugate vaccine throughout the entire series 1
• However, if the previous vaccine type is unknown, ensure infants aged 2-6 months receive a minimum of 3 doses total of any conjugate vaccine 1

Simultaneous Administration

• Hib vaccines can be given simultaneously with DTP, MMR, OPV, IPV, pneumococcal, and meningococcal vaccines 1
• All conjugate vaccines should be administered intramuscularly 1

Common Pitfall to Avoid

The DTaP-IPV-Hib-HepB combination vaccine has a minimum age of 24 weeks for the third dose, making it unsuitable for accelerated pertussis protection schedules that use 4-week intervals 1. If early pertussis protection is needed, use a different vaccine formulation.