Immunizations: Schedule Principles and Contraindications

Pediatrics · Immunizations & Preventive Care·Updated 2026-10-28

What it is

Vaccines produce active immunity by exposing the immune system to an inactivated or weakened antigen. Live attenuated vaccines (MMR, varicella, rotavirus, intranasal influenza) replicate in the body, so they are withheld when the immune system cannot contain them, as in severe immunosuppression and pregnancy. Inactivated vaccines cannot cause infection and are safe in pregnancy and immunosuppression.

What the NCLEX focuses on

Vaccines are timed by chronological age; preterm infants receive full doses at the same ages as term infants, not by corrected age.
Schedule landmarks: hepatitis B starts at birth; DTaP, IPV, Hib, PCV and rotavirus start at 2 months; MMR and varicella at 12 to 15 months and again at 4 to 6 years; influenza yearly from 6 months; Tdap, HPV and MenACWY at 11 to 12 years.
Rotavirus is oral; dose 1 is given by 14 weeks 6 days and the series is never started later. It is contraindicated after intussusception and in severe combined immunodeficiency.
True contraindication to any vaccine: anaphylaxis to a previous dose or a vaccine component. Encephalopathy within 7 days of a pertussis-containing dose contraindicates further pertussis vaccine.
Live vaccines are deferred for severe immunosuppression (chemotherapy, high-dose corticosteroids), pregnancy, and after IVIG or blood products (up to 11 months after high-dose IVIG).
False contraindications (vaccinate): mild illness with or without low-grade fever, current antibiotics, prematurity, breastfeeding, a pregnant or immunosuppressed household member, egg allergy, a family history of seizures or adverse events, and a local reaction to a previous dose.
Moderate or severe acute illness is a precaution: defer until improved.

Priority nursing actions

Screen before every dose: previous reactions, allergies, current illness, immune status, steroid use, pregnancy, and recent blood products or IVIG.
Give the current Vaccine Information Statement (VIS).
Give IM vaccines in the vastus lateralis for infants and the deltoid for older children; separate injection sites by at least 1 inch.
Keep epinephrine available and observe for anaphylaxis; keep adolescents seated for 15 minutes because of syncope.
Document date, vaccine, lot number, manufacturer, site, route, VIS date and administrator; report adverse events to VAERS.

Numbers to know

Item	Rule	Why it matters
Rotavirus	Dose 1 by 14 weeks 6 days; last dose by 8 months 0 days	No safety data for older infants
Two live injectable vaccines	Same day or at least 28 days apart	A second live vaccine given too soon responds poorly
High-dose prednisone	2 mg/kg/day or 20 mg/day or more for 14 days or longer	Defer live vaccines until 1 month after stopping
Pregnancy after MMR or varicella	Avoid for 4 weeks	Theoretical fetal risk from a live virus
Fever after DTaP	105 F (40.5 C) or higher within 48 hours	Precaution reviewed before the next dose
Infant of HBsAg-positive mother	Hepatitis B vaccine plus HBIG within 12 hours of birth	Prevents perinatal infection

Common exam traps

Choosing to defer vaccines for a cold, low-grade fever or an antibiotic course: wrong because these are not contraindications.
Choosing to wait for a preterm infant's corrected age: wrong because the schedule follows chronological age.
Choosing to withhold MMR because the mother is pregnant or a sibling receives chemotherapy: wrong because MMR is not transmitted; vaccinating contacts protects them.
Choosing to withhold influenza vaccine for egg allergy: wrong because any age-appropriate influenza vaccine is given regardless of egg allergy severity.

What to teach

Expect soreness, redness, fussiness and low-grade fever for 1 to 2 days; fever or rash can appear 1 to 2 weeks after MMR or varicella.
Use weight-based acetaminophen or ibuprofen for discomfort; never give aspirin (Reye syndrome), and avoid salicylates for 6 weeks after varicella vaccine.
Cover any varicella vaccine blisters and avoid contact with immunocompromised people until they crust.
Call for fever of 105 F (40.5 C) or higher, a seizure, crying for 3 hours or more, limpness, or hives, swelling or trouble breathing.

Try 2 NCLEX-style questions on this topic

From the NCLEXPace question bank. Pick your answers, then check them inside NCLEXPace.

Question 1 · QID D2ADD16A

The nurse screens a 12-month-old who is due for the first MMR and varicella doses. Evaluate each history finding independently and indicate whether to defer these vaccines today or whether the child may be vaccinated if otherwise eligible.

For each finding, indicate whether to defer MMR and varicella today or whether the child may be vaccinated if otherwise eligible.

	Defer today	May vaccinate
Finished a 10-day course of amoxicillin for otitis media yesterday
Mother is 24 weeks pregnant
Receives prednisone 2 mg/kg/day, started 21 days ago
Received IVIG 2 g/kg for Kawasaki disease 5 months ago
Older sibling at home is receiving chemotherapy for leukemia

Question 2 · QID 34D1BD57

A 6-month-old is due for the third DTaP dose. Which report by the caregiver about the previous dose requires the nurse to withhold the vaccine and notify the provider?

Select the best answer.

A. Marked redness and swelling extending across most of the injected thigh for about 3 days before gradually resolving
B. Unexplained seizures with hours of unresponsiveness that began 3 days after the dose
C. A family history of an older sibling having a febrile seizure several hours after receiving a previous DTaP dose
D. A temperature of 103.1 F (39.5 C) that developed the evening after the previous dose and resolved by the next day

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Sources

Kroger A, Bahta L, Long S, Sanchez P. General Best Practice Guidelines for Immunization. Advisory Committee on Immunization Practices (ACIP). Centers for Disease Control and Prevention.
American Academy of Pediatrics. Recommended Child and Adolescent Immunization Schedule, United States. AAP.
Grohskopf LA, Blanton LH, Ferdinands JM, et al. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States, 2024-25 Influenza Season. MMWR Recomm Rep. 2024;73(5):1-25.
Hockenberry MJ, Duffy EA, Gibbs KD. Wong's Nursing Care of Infants and Children. 12th ed. Elsevier; 2024.

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