Routine vaccination

4-dose series (3-dose primary series at age 2, 4, and 6 months, followed by a booster dose at age 18 months)

Catch-up vaccination

• Dose 1 at age 7–11 months: Administer dose 2 at least 4 weeks later and dose 3 (final dose) at age12–15 months or 8 weeks after dose 2 (whichever is later).
• Dose 1 at age 12–14 months: Administer dose 2 (final dose) at least 8 weeks after dose 1.
• Dose 1 before age 12 months and dose 2 before age 15 months: Administer dose 3 (final dose) at least 8 weeks after dose 2.
• 1 dose administered at age 15 months or older: No further doses needed
• Unvaccinated at age 15–59 months: Administer 1 dose.
• Previously unvaccinated children age 60 months or older who are not considered high risk: Do not require catch-up vaccination

Special situations

• Chemotherapy or radiation treatment:

  Age 12–59 months
  - Unvaccinated or only 1 dose before age 12 months: 2 doses, 8 weeks apart
  - 2 or more doses before age 12 months: 1 dose at least 8 weeks after previous dose

  Doses administered within 14 days of starting therapy or during therapy should be repeated at least 3 months after therapy completion.

• Hematopoietic stem cell transplant (HSCT):

  - 3-dose series 4 weeks apart starting 6 to 12 months after successful transplant, regardless of Hib vaccination history

• Anatomic or functional asplenia (including sickle cell disease):

  Age 12–59 months
  - Unvaccinated or only 1 dose before age 12 months: 2 doses, 8 weeks apart
  - 2 or more doses before age 12 months:
  1 dose at least 8 weeks after previous dose
  Unvaccinated* persons age 5 years or older
  - 1 dose

• Elective splenectomy:
  Unvaccinated* persons age 15 months or older
  - 1 dose (preferably at least 14 days before procedure)

• HIV infection:
  Age 12–59 months
  - Unvaccinated or only 1 dose before age 12 months: 2 doses, 8 weeks apart
  - 2 or more doses before age 12 months:
  1 dose at least 8 weeks after previous dose
  Unvaccinated* persons age 5–18 years
  - 1 dose

• Immunoglobulin deficiency, early component complement deficiency:
  Age 12–59 months
  - Unvaccinated or only 1 dose before age 12 months: 2 doses, 8 weeks apart
  - 2 or more doses before age 12 months:
  1 dose at least 8 weeks after previous dose
  * Unvaccinated = Less than routine series (through age 14 months) OR no doses (age 15 months or older)