Vaccine Academy › Vaccine School › Childhood and adolescent
Content current as of October 11, 2026. AI-assisted draft; not yet reviewed by a licensed pharmacist. Current CDC schedules: immunization schedules.
- The disease and why it matters
- Video and figures
- Get CE credit
- Products available
- Who should get it
- Dosing and schedule, including catch-up
- Administration
- Storage and handling
- Contraindications and precautions
- Safety and adverse events
- Special populations
- Counseling pearls for the pharmacy counter
- Common patient questions
- References
The disease and why it matters
Haemophilus influenzae infections range from minor to serious and even deadly; CDC says chemoprophylaxis and vaccination are recommended to prevent one type of H. influenzae disease, type b (Hib), and that other H. influenzae disease is uncommon but has been increasing in recent years. [1]
Before Hib vaccine, Hib disease was the leading cause of bacterial meningitis among children under 5 years old in the United States; Hib infections usually affect children under 5 years of age but can also affect adults with certain medical conditions, and can cause pneumonia, severe throat swelling, infections of the blood, joints, bones and covering of the heart, and death. [2]
Transmission usually occurs when someone breathes in or has direct contact with respiratory droplets containing the bacteria, and nasopharyngeal carriers can spread the bacteria; groups at increased risk of Hib disease include unimmunized and underimmunized children younger than 5 years, household contacts of someone with Hib disease, and daycare classmates of someone with Hib disease. [1]
Video and figures
Video
Get CE credit
- CDC You Call the Shots: Haemophilus influenzae type b module (CDC TRAIN course WB4687) — CDC · Free (CDC states no fees for its CE activities) · accredited by CDC, jointly accredited by ACCME, ACPE and ANCC; pharmacy UAN JA4008229-0000-23-060-H06-P. CDC's listing shows credit expiring 7/17/2025, so confirm on CDC TRAIN that credit is still available · link confirmed October 11, 2026
RxEvidence is not an accredited continuing education provider and does not award CE credit. These are links to activities offered by others.
Products available
CDC lists three Hib-only conjugate vaccines (ActHIB, Hiberix and PedvaxHIB) and two combination vaccines that contain Hib (Pentacel and Vaxelis). [3]
| Vaccine | Manufacturer (FDA page) | FDA-approved use | Initial U.S. approval |
|---|---|---|---|
| ActHIB | Sanofi Pasteur Inc. [4] | Prevention of invasive disease caused by H. influenzae type b; approved for use as a four-dose series in infants and children 2 months through 5 years of age [5] | 1993 [5] |
| Hiberix | GlaxoSmithKline Biologicals S.A. [6] | Prevention of invasive disease caused by H. influenzae type b; approved for use in children aged 6 weeks through 4 years (prior to fifth birthday) [7] | 2009 [7] |
| PedvaxHIB (liquid) | Merck Sharp & Dohme Corp. [8] | Routine vaccination against invasive disease caused by H. influenzae type b in infants and children 2 to 71 months of age [9] | Not stated in the posted label |
The PedvaxHIB document posted on FDA's page is an older-format label without a highlights section or a revision date, and the FDA page is marked content current as of 04/24/2019; ActHIB's page is content current as of 10/14/2022 (label revised 3/2022) and Hiberix's as of 12/17/2025 (label revised 12/2025). Check the current manufacturer labeling before relying on this summary of PedvaxHIB. [8] [4] [5] [6] [7]
Who should get it
CDC / ACIP (Hib vaccine recommendations page, September 22, 2025)
As of September 22, 2025
CDC recommends Hib vaccination for children younger than 5 years old, beginning at age 2 months (the first dose may be given as early as 6 weeks); CDC recommends Hib vaccination for older children and adults only in special situations. [3]
FDA labels (ActHIB, Hiberix, PedvaxHIB)
As of December 17, 2025
The labels give different upper ages: ActHIB 2 months through 5 years of age, Hiberix 6 weeks through 4 years (prior to the fifth birthday), and liquid PedvaxHIB 2 to 71 months; the PedvaxHIB label states it is not recommended for use in infants younger than 6 weeks because of the potential for immune tolerance. [5] [7] [9]
CDC does not recommend Hib vaccination for most people aged 5 years or older unless they have certain medical conditions and are unvaccinated, or receive a hematopoietic stem cell transplant; Hib vaccination is recommended for children and adults following successful hematopoietic stem cell transplant regardless of Hib vaccination history. [3]
CDC says Hib vaccination may be recommended depending on vaccination history for children with chemotherapy or radiation treatment, anatomic or functional asplenia (including sickle cell disease), elective splenectomy, HIV infection, or immunoglobulin deficiency or early component complement deficiency, and for adults with anatomical or functional asplenia (including sickle cell disease). [3]
CDC: January 2026 schedule revision and its legal status (Hib)
As of June 11, 2026
On January 5, 2026 the CDC Acting Director approved a revised childhood and adolescent schedule whose first category (recommended for all children) lists measles, mumps, rubella, polio, pertussis, tetanus, diphtheria, Hib, pneumococcal disease, HPV and varicella, so Hib stayed in the all-children category. A federal district court stayed that schedule on March 16, 2026 and reverted it to the version as of May 2025, and CDC's schedule page continues to show the July 2, 2025 addendum edition. [10] [11] [12]
American Academy of Pediatrics 2026 schedule (endorsed by AAFP, ACOG, AMA, IDSA, APhA and others)
As of January 26, 2026
The AAP published its own 2026 schedule on January 26, 2026, which continues to recommend routine immunization for protection against 18 diseases, including RSV, hepatitis A, hepatitis B, rotavirus, influenza and meningococcal disease, and differs from the schedule recently issued by CDC; the AAP schedule is formally endorsed by 12 organizations, including AAFP, ACOG, AMA, IDSA and the American Pharmacists Association. [13]
Dosing and schedule, including catch-up
| Product | Series |
|---|---|
| ActHIB, Hiberix, Pentacel or Vaxelis | 4-dose series: a 3-dose primary series at age 2, 4 and 6 months, followed by a booster dose at age 12 to 15 months (Vaxelis is not recommended for use as a booster dose; a different Hib-containing vaccine should be used for the booster). [14] |
| PedvaxHIB | 3-dose series: a 2-dose primary series at age 2 and 4 months, followed by a booster dose at age 12 to 15 months. [14] |
| American Indian and Alaska Native infants | Vaxelis and PedvaxHIB are preferred over other Hib vaccines for the primary series. [14] |
The CDC recommendations page says the booster dose at age 12 through 15 months should be given at least 8 weeks after the most recent Hib vaccination and will be dose 3 or 4 depending on the vaccine used in the primary series; Vaxelis is only indicated at ages 2, 4 and 6 months and should not be used for the booster. [3]
| Vaccine | Dose and schedule in the label |
|---|---|
| ActHIB | Four-dose series (0.5 mL each) by intramuscular injection: a three-dose primary series at 2, 4 and 6 months of age and a single booster dose at 15 to 18 months of age. [5] |
| Hiberix | A 4-dose series (approximately 0.5 mL each) by intramuscular injection: one dose each at 2, 4 and 6 months of age (the first dose may be given as early as 6 weeks) and a booster dose at 15 through 18 months. [7] |
| PedvaxHIB (liquid) | Infants 2 to 14 months: a 0.5 mL dose, ideally beginning at 2 months, followed by a 0.5 mL dose 2 months later; when the primary two-dose regimen is completed before 12 months, a booster is required at 12 to 15 months and not earlier than 2 months after the second dose; children 15 months and older previously unvaccinated get a single 0.5 mL dose. [9] |
CDC catch-up guidance (July 2, 2025 notes): dose 1 at age 7 to 11 months, give dose 2 at least 4 weeks later and dose 3 (final) at age 12 to 15 months or 8 weeks after dose 2, whichever is later; dose 1 at 12 to 14 months, dose 2 (final) at least 8 weeks after dose 1; two doses of PedvaxHIB before age 12 months, dose 3 (final) at age 12 to 59 months and at least 8 weeks after dose 2; 1 dose at age 15 months or older, no further doses; unvaccinated at 15 to 59 months, 1 dose; children 60 months or older not at high risk, catch-up not required. [14]
| Condition | Dosing |
|---|---|
| Chemotherapy or radiation treatment, age 12 to 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 the previous dose; doses given within 14 days of starting therapy or during therapy should be repeated at least 3 months after therapy completion. [14] |
| Hematopoietic stem cell transplant (children and adults) | 3-dose series 4 weeks apart starting 6 to 12 months after successful transplant, regardless of Hib vaccination history. [14] [15] |
| Anatomic or functional asplenia (including sickle cell disease) | Age 12 to 59 months: unvaccinated or only 1 dose before age 12 months, 2 doses 8 weeks apart; 2 or more doses before 12 months, 1 dose at least 8 weeks after the previous dose; unvaccinated persons aged 5 years or older (and adults), 1 dose. [14] [15] |
| Elective splenectomy | Unvaccinated persons 15 months or older: 1 dose, preferably at least 14 days before the procedure. [14] |
| HIV infection | Age 12 to 59 months: unvaccinated or only 1 dose before age 12 months, 2 doses 8 weeks apart; 2 or more doses before 12 months, 1 dose at least 8 weeks after the previous dose; unvaccinated persons 5 to 18 years, 1 dose. [14] |
| Immunoglobulin deficiency, early component complement deficiency, or early component complement inhibitor use | Age 12 to 59 months: unvaccinated or only 1 dose before age 12 months, 2 doses 8 weeks apart; 2 or more doses before 12 months, 1 dose at least 8 weeks after the previous dose. [14] |
The PedvaxHIB label says that if PedvaxHIB is given in a series with one of the other products licensed for infants, the recommended number of doses to complete the series is determined by the other product and not by PedvaxHIB, and that PedvaxHIB may be interchanged with other licensed Hib conjugate vaccines for the booster dose. [9]
CDC says Vaxelis can be used for catch-up vaccination in children younger than age 5 years and that the catch-up schedule should be followed even if Vaxelis is used for one or more doses. [14]
Administration
- ActHIB and Hiberix are given as 0.5-mL intramuscular injections after reconstitution of the lyophilized vaccine with the accompanying saline diluent only; liquid PedvaxHIB is a 0.5-mL intramuscular injection and must not be injected intravenously. [5] [7] [9]
- To reconstitute ActHIB, withdraw 0.6 mL of saline diluent, inject it into the vial of lyophilized ActHIB and agitate the vial to ensure complete reconstitution. [5]
- If there is an interruption or delay between doses in the primary series, there is no need to repeat the series; dosing should continue at the next clinic visit. [9]
- Infants born prematurely should be vaccinated with PedvaxHIB at the same chronological age and according to the same schedule and precautions as full-term infants and children. [9]
- Hib vaccination can be given at the same time as other vaccines; CDC notes that the Hib-containing combination vaccines (Pentacel, Vaxelis) count toward the Hib series and the schedule should be followed even if Vaxelis is used for some doses. [14]
Storage and handling
- ActHIB: store lyophilized ActHIB vaccine packaged with saline diluent at 2 to 8 °C (35 to 46 °F); do not freeze; discard unused portion. [5]
- Hiberix: store lyophilized antigen component vials refrigerated at 2 to 8 °C (36 to 46 °F) and protect from light; the sterile saline diluent prefilled syringes may be stored refrigerated or at controlled room temperature between 2 and 25 °C (36 and 77 °F); do not freeze and discard the diluent if frozen. [7]
- Liquid PedvaxHIB: store the vaccine at 2 to 8 °C (36 to 46 °F); do not freeze. [9]
Contraindications and precautions
| Source | Contraindications | Precautions |
|---|---|---|
| CDC appendix (July 2, 2025 edition) | Severe allergic reaction (e.g., anaphylaxis) after a previous dose or to a vaccine component; younger than age 6 weeks. [16] | Moderate or severe acute illness with or without fever. [16] |
| ActHIB label | Severe allergic reaction (e.g., anaphylaxis) after a previous dose of any H. influenzae type b- or tetanus toxoid-containing vaccine or any component of ActHIB. [5] | If Guillain-Barré syndrome occurred within 6 weeks of receipt of a prior tetanus toxoid-containing vaccine, the potential benefits and risks of giving ActHIB must be evaluated. [5] |
| Hiberix label | Severe allergic reaction (e.g., anaphylaxis) after a previous dose of any H. influenzae type b- or tetanus toxoid-containing vaccine or any component of Hiberix. [7] | If GBS has occurred within 6 weeks of receipt of a prior tetanus toxoid-containing vaccine, the decision to give Hiberix should be based on potential benefits and risks; syncope and apnea in premature infants are also noted. [7] |
| PedvaxHIB label | Hypersensitivity to any component of the vaccine or the diluent; persons who develop symptoms suggestive of hypersensitivity after an injection should not receive further injections. [9] | Use caution when vaccinating latex-sensitive individuals because the vial stopper contains dry natural latex rubber that may cause allergic reactions. [9] |
Safety and adverse events
ActHIB: following ActHIB in children 2 to 20 months of age, the most frequent systemic reactions after any dose in children 2 to 16 months were fussiness/irritability (75%), inconsolable crying (58%) and decreased activity/lethargy (51%); in children 15 to 20 months of age tenderness (20%) was the most common local reaction after a single dose. [5]
Hiberix: common solicited adverse reactions (20% or more) were pain and redness at the injection site, irritability, drowsiness, fever, loss of appetite, fussiness and restlessness. [7]
PedvaxHIB: in a study of 678 infants 2 to 6 months of age, both formulations were generally well tolerated and no serious vaccine-related adverse reactions were reported; post-marketing reports include lymphadenopathy, rarely angioedema, febrile seizures and sterile injection-site abscess. [9]
Urine antigen detection may not have diagnostic value in suspected Hib disease within 1 to 2 weeks after receipt of a Hib-containing vaccine, including ActHIB, because Hib capsular polysaccharide derived from conjugate vaccines has been detected in the urine of some vaccinees. [5]
Hiberix: syncope can occur with injectable vaccines and procedures should be in place to avoid falling injury; apnea has been observed in some infants born prematurely and the decision about timing should be based on the infant's medical status and the potential benefits and risks. [7]
Special populations
Hib vaccination is recommended after successful hematopoietic stem cell transplant, before elective splenectomy (preferably at least 14 days before the procedure) and in people with asplenia, as detailed in the dosing section. [3] [14]
Pregnancy: the ActHIB label says it is not approved for individuals 6 years of age and older and that no human or animal data are available to assess vaccine-associated risks in pregnancy; the PedvaxHIB label says it is not recommended for use in individuals 6 years of age and older and that animal reproduction studies have not been conducted. [5] [9]
Altered immunocompetence: immune responses to the vaccine may be reduced in people with altered immunocompetence, and the ActHIB label lists "Altered Immunocompetence" as a warning (section 5.3). [5]
Counseling pearls for the pharmacy counter
- Hib vaccine is usually given in 3 or 4 doses (depending on brand); infants usually get their first dose at 2 months and complete the series at 12 to 15 months. [2]
- Hib infection can cause severe illness such as meningitis and infections of the blood, and before Hib vaccine it was the leading cause of bacterial meningitis in children under 5 years of age in the United States. [2]
- Parents and guardians must be informed of the benefits and risks of the vaccine and of the importance of completing the immunization series unless a contraindication exists. [5]
Common patient questions
Which Hib products need 3 doses and which need 4?
Per CDC, ActHIB, Hiberix, Pentacel and Vaxelis use a 4-dose series (3 primary doses plus a booster at 12 to 15 months) and PedvaxHIB uses a 3-dose series (2 primary doses plus a booster at 12 to 15 months). [14]
A 2-year-old with sickle cell disease has never had Hib vaccine. What now?
For age 12 to 59 months with asplenia (including sickle cell disease) who are unvaccinated or had only 1 dose before age 12 months, CDC lists 2 doses 8 weeks apart. [14]
Is Hib vaccine needed for a healthy 7-year-old who never got it?
No. CDC says previously unvaccinated children 60 months or older who are not considered high risk do not need catch-up vaccination. [14]
Can Vaxelis be the booster at 12 to 15 months?
No. Vaxelis is only indicated at ages 2, 4 and 6 months; CDC says a different Hib-containing vaccine should be used for the booster dose. [3]
References
- Centers for Disease Control and Prevention. Clinical overview of Haemophilus influenzae disease. Page dated September 22, 2025. Accessed October 11, 2026. https://www.cdc.gov/hi-disease/hcp/clinicians/index.html. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Hib (Haemophilus influenzae type b) vaccine: what you need to know. Vaccine Information Statement, August 6, 2021. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/current-vis/hib.html. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Hib vaccine recommendations (for health care providers). Page dated September 22, 2025. Accessed October 11, 2026. https://www.cdc.gov/hi-disease/hcp/vaccine-recommendations/index.html. Accessed October 11, 2026.
- U.S. Food and Drug Administration. ActHIB product page (content current as of 10/14/2022). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/acthib. Accessed October 11, 2026.
- ActHIB (Haemophilus b conjugate vaccine [tetanus toxoid conjugate]), solution for intramuscular injection: prescribing information, revised 3/2022. Sanofi Pasteur Inc. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/74395/download?attachment. Accessed October 11, 2026.
- U.S. Food and Drug Administration. Hiberix product page (content current as of 12/17/2025). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/hiberix. Accessed October 11, 2026.
- HIBERIX (Haemophilus b conjugate vaccine [tetanus toxoid conjugate]), for intramuscular use: prescribing information, revised 12/2025. GlaxoSmithKline Biologicals S.A. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/77017/download?attachment. Accessed October 11, 2026.
- U.S. Food and Drug Administration. Haemophilus b conjugate vaccine (meningococcal protein conjugate), PedvaxHIB, product page (content current as of 04/24/2019). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/haemophilus-b-conjugate-vaccine-meningococcal-protein-conjugate. Accessed October 11, 2026.
- Liquid PedvaxHIB [Haemophilus b conjugate vaccine (meningococcal protein conjugate)]: package insert as posted on FDA's product page (no revision date appears on the posted document; its heading carries a placeholder). Merck Sharp & Dohme. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/80438/download?attachment. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. CDC acts on Presidential Memorandum to update childhood immunization schedule. News release, January 5, 2026. Accessed October 11, 2026. https://www.cdc.gov/media/releases/2026/2026-cdc-acts-on-presidential-memorandum-to-update-childhood-immunization-schedule.html. Accessed October 11, 2026.
- Congressional Research Service. The 2026 Childhood Immunization Schedule (R48982). June 11, 2026. Accessed October 11, 2026. https://www.congress.gov/crs_external_products/R/PDF/R48982/R48982.1.pdf. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Healthcare professionals: immunization schedules. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/index.html. Accessed October 11, 2026.
- American Academy of Pediatrics. AAP releases recommended childhood and adolescent immunization schedule for 2026. HealthyChildren.org news. Accessed October 11, 2026. https://healthychildren.org/English/news/Pages/AAPs-recommended-childhood-and-adolescent-immunization-schedule-for-2026.aspx. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Child and adolescent immunization schedule notes: recommendations for ages 18 years or younger, United States, 2025. July 2, 2025. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/child-adolescent-notes.html. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Adult immunization schedule notes: recommendations for ages 19 years or older, United States, 2025. July 2, 2025. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/adult-notes.html. Accessed October 11, 2026.
- Centers for Disease Control and Prevention. Child and adolescent immunization schedule appendix: guide to contraindications and precautions (July 2, 2025 edition). Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/child-adolescent-appendix.html. Accessed October 11, 2026.
For professional education. Check current labeling and guidance before acting. Not medical advice.
