Review of Pediatric Immunizations

Educational Objectives

The goal of this program is to improve management of pediatric immunizations. After hearing and assimilating this program, the clinician will be better able to:

1. Follow typical monovalent pediatric immunization schedules.
2. Optimize administration of live vaccinations.
3. Select appropriate candidates for administration of combination vaccinations.

Summary

Hepatitis B vaccine: a baby weighing 3000 g born to a mother with hepatitis B surface antigen (HBsAg) positivity should receive the hepatitis B vaccine and hepatitis B immune globulin (HBIG) ≤12 hr after birth to reduce the risk for perinatal hepatitis B virus (HBV) transmission; infants born to mothers with unknown HBsAg status only need the hepatitis B vaccine ≤12 hr after birth; the mother can then be tested, and if the mother has HBsAg positivity, HBIG should be given ≤1 wk after birth; administer HBIG and the hepatitis B vaccine ≤12 hr after birth to an infant weighing <2000 g and born to a mother with unknown HBsAg status

Breastfeeding: mothers with HBV can breastfeed an infant immunized against HBV, as transmission is unlikely (despite HBV passage through breastmilk); mothers with hepatitis C virus can also breastfeed; mothers who have HIV positivity but not receiving antiretroviral therapy (ART) are advised not to breastfeed because of concern for HIV transmission; however, women receiving ART who have a viral load <50 copies/mL can breastfeed, as risk for transmission is relatively low

Administration of combination diphtheria tetanus pertussis (DTaP)/HBV vaccine/inactivated poliovirus vaccine (IPV; eg, Pediarix): if an infant received their first HBV vaccine at the hospital, then Pediarix can be administered at the recommended intervals of 2, 4, and 6 mo; thus, the patient can receive 4 HBV vaccines after birth; clinicians often avoid administering Pediarix to infants who are not due for their third dose of HBV vaccine, and, instead, separately administer vaccinations against inactivated poliovirus and DTaP; however, administering Pediarix has not been associated with increased vaccine reactions and also results in higher final HBV antibody titers, which may correlate with a longer duration of detectable antibody; Pediarix can be administered at 2, 4, and 6 mo, regardless of whether the infant received vaccination against HBV at birth

Mercury in vaccines: only a few vaccines contain thimerosal, a form of mercury that differs from the mercury found in the environment (eg, fish); most vaccines are mercury-free, and thimerosal was removed from all childhood vaccines in the United States in 2001; the tetanus-diphtheria vaccine (administered only to adults), combination hepatitis A and B vaccine, multidose influenza vaccine vials (5 mL), and multidose meningococcal vaccine vials still contain thimerosal; thimerosal is added to multidose vials as a preservative to prevent growth of bacteria and fungi; mercury is a naturally-occurring element that is converted by bacteria to methylmercury, which makes its way through the food chain in fish, animals, and humans; high levels of methylmercury can be toxic; thimerosal is converted into ethylmercury, which is easily metabolized and more rapidly excreted than methylmercury

Oral rotavirus (RV) vaccine: schedule — the first dose of the oral RV vaccine should be administered in patients <15 wk of age (not advised in children ≥15 wk of age); the maximum age for the last dose is 8 mo and 0 days (series completion is unnecessary in older patients); the minimum interval between doses is 4 wk; due to increased risk for intussusception, the first dose cannot be administered before 6 wk of age; the risk for intussusception is highest with the first RV vaccine dose; if no issues occur after the first dose, patients can safely receive second and third doses before 8 mo of age; intussusception typically occurs ≤2 wk after the first dose; administration of RV5 is recommended at 2 mo, 4 mo, and 6 mo of age, while administration of RV1 is recommended at 2 mo and 4 mo of age; according to the respective package inserts, the maximum age for the final dose of RV5 is 32 wk, and the maximum age for the final dose of RV1 is 24 wk; the Advisory Committee on Immunization Practices recommends completing either vaccine series by 8 mo and 0 days of age; vaccination pearls — no data exist regarding the benefits or risks associated with dose readministration; administer the initial vaccine while the infant is happy to ensure proper swallowing; if some portion of the injection is not swallowed, consider giving another dose

Influenza vaccine: recommended for children ≥6 mo of age; children 6 mo to 8 yr of age — need 2 doses of the influenza vaccine during their first year of vaccination; children who received only one dose the previous year need 2 doses in the subsequent year; booster injection is not needed in subsequent seasons after receiving 2 flu injections within the same season or 2 consecutive seasons; children ≥9 yr of age — need one dose each season, regardless of vaccination history; a second dose is recommended for children who receive the initial vaccination at 8 yr old and turn 9 during the flu season; children 6 mo to 35 mo of age — should receive the pediatric dose (0.25 mL); administer the adult dose (0.5 mL) starting at 3 yr of age

Varicella vaccine: varicella is a live virus vaccine; multiple live-virus vaccines can be administered on the same day, but the immune response to live-virus vaccines might be impaired if administered within 28 days of another live-virus vaccine; Verstraeten et al (2003) demonstrated a 3-fold greater risk for varicella vaccine failure among patients receiving the vaccine <28 days after the measles, mumps, and rubella (MMR) vaccination; wait ≥4 wk between live-virus vaccine doses; a non-live vaccine can be administered at any time; wait ≥4 wk following live-virus vaccine administration before administering tuberculin skin testing, as live-virus vaccination can transiently suppress test reactivity; tuberculin skin testing and live-virus vaccination can be administered at the same visit without any issues

Haemophilus influenzae type b (Hib) vaccine and pneumococcal conjugate vaccine (PCV): Hib vaccine and PCV are not needed in children >59 mo of age; Hib vaccine and PCV are recommended for administration at 2 mo, 4 mo, and 6 mo of age, and once between 12 to 15 mo of age; children 15 mo to 59 mo of age who missed previous Hib injections should receive one Hib injection; children 24 mo to 59 mo of age who have not previously received a PCV dose should receive just one dose

Inactivated poliovirus vaccine: though children only need 4 IPVs, the Centers for Disease Control and Prevention (CDC) advises a booster dose for all children 4 to 6 yr of age, regardless of number of IPVs received before that point; if a patient has received only 2 IPVs before 4 yr of age, then only 1 booster is needed (a fourth dose is not necessary if the third dose was administered ≥6 mo after the previous dose in a patient ≥4 yr of age); the DTaP-IPV combination vaccination (Kinrix) can be administered in children 4 to 6 yr of age

Quadrivalent MMR and varicella (MMRV) vaccine: though MMRV vaccination is approved for children ≥1 yr of age, fever and febrile seizures are twice as likely to occur in children <4 yr of age who receive the MMRV vaccination, compared with separate MMR and varicella vaccinations; the antigenic load of the varicella component in the MMRV vaccination is 7-fold higher than the antigenic load in the standalone varicella vaccination; fever typically develops ≥5 days following administration of a live-virus vaccine, compared with onset 1 to 3 days following administration of a non-live virus vaccine; 5% to 15% of patients who receive the MMR vaccine will develop low-grade fever and/or mild rash 7 to 12 days after vaccination; no increased risk for febrile seizures exists among children ≥4 yr of age receiving MMRV; children with a personal or family history of seizures should avoid receiving MMRV and instead receive separate MMR and varicella vaccines

Meningococcal vaccines: meningococcal serogroups A, C, W, or Y (MenACWY) — first-year college students living in dormitories are at high risk of contracting meningococcal meningitis caused by meningococcal serogroups A, C, W, or Y; only one MenACWY vaccination is required after 16 yr of age, regardless of vaccination history; though vaccination is indicated between 11 and 21 yr of age, the CDC recommends that adult-aged students living in dormitories receive vaccination if not already received after 16 yr of age; meningococcal B virus vaccine — strongly recommended for students before they enter college or military services; Bexsero is a 2-shot series given ≥1 mo apart; Trumenba is a 3-shot series given at time 0, 1 to 2 mo following initial injection, then 6 mo following initial injection (though only 2 shots are needed if 6 mo elapses between the first 2 doses); Bexsero and Trumenba are not interchangeable; combination vaccination — Penbraya offers vaccination against MenACWY and MenB, but a separate Trumenba vaccine is needed 6 mo following injection administration in patients ≥16 yr of age

Readings

Badell ML, Prabhu M, Dionne J, et al. Society for Maternal-Fetal Medicine consult series #69: hepatitis B in pregnancy: updated guidelines. Am J Obstet Gynecol. 2024;230(4):pB2–B11. doi:10.1016/j.ajog.2023.12.023. View Article; Bigham J. Understanding the updated hepatitis B vaccination recommendations and guidance. FPM. 2023;30(5):p9–12. View Article; Chiu M, Bao C, Sadarangani M. Dilemmas with rotavirus vaccine: the neonate and immunocompromised. Pediatr Infect Dis J. 2019;38(6S):pS43–S46. doi:10.1097/INF.0000000000002322. View Article; Clark C, Winograd SM. Pediatric febrile and first-time seizures. Emerg Med Rep. 2022;43(359):p0. View Article; Ehrhardt S, Xie C, Guo N, et al. Breastfeeding while taking lamivudine or tenofovir disoproxil fumarate: a review of the evidence. Clin Infect Dis. 2015;60(2):275-278. doi:10.1093/cid/ciu798. View Article; Lapphra K, Scheifele D. Does vaccination with the varicella vaccine within four weeks after the measles, mumps and rubella vaccine reduce protection? Paediatr Child Health. 2009;14(8):501. doi:10.1093/pch/14.8.501. View Article; Marshall GS, Petigara T, Liu Z, et al. Timing of monovalent vaccine administration in infants receiving DTaP-based combination vaccines in the United States. Pediatr Infect Dis J. 2022;41(9):p775–781. doi:10.1097/INF.0000000000003609. View Article; Michels S, Daley M, Newcomer S. Completion of multidose vaccine series in early childhood: current challenges and opportunities. Curr Opin Infect Dis. 2024;37(3):176-184. doi:10.1097/QCO.0000000000001007. View Article; Tosh PK, Jacobson RM, Poland GA. Influenza vaccines. Mayo Clin Proc. 2010;85(3):p257–273. doi:10.4065/mcp.2009.0615. View Article.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Lee was recorded exclusively for Audio Digest on July 15, 2024. Audio Digest thanks Dr. Lee for his cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 1.25 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 1.25 CE contact hours.

Lecture ID:

FP723801

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.