Immunization in Immunocompromised Child

General Principles

Immunocompromised state increases susceptibility to severe vaccine-preventable diseases.
Inactivated, killed, and subunit vaccines remain safe.
Vaccine efficacy potentially compromised; additional doses or higher antigen content required.
Antibody titer monitoring required to ensure seroprotection.
Live vaccines contraindicated in severe immunodeficiency.
Mild to moderate immunodeficiency permits live vaccines if benefits outweigh risks.
Household contacts must avoid transmissible live vaccines, notably oral polio vaccine (OPV).
Nontransmissible live vaccines, including measles, mumps, rubella (MMR) and varicella, remain safe for household contacts.
Postexposure prophylaxis requires specific immunoglobulins for major exposures (rabies, tetanus, varicella), irrespective of prior vaccination history.

Vaccine administration depends upon specific immune compartment defects.

Disorders include X-Linked Agammaglobulinemia (XLA) and common variable immunodeficiency (CVID).
All live vaccines contraindicated.
Annual inactivated influenza vaccine (IIV) recommended.
Protection primarily provided via immunoglobulin replacement therapy.

Disorders include Severe Combined Immunodeficiency (SCID) and complete DiGeorge syndrome.
All live viral and bacterial vaccines absolutely contraindicated.
Inactivated vaccines deemed safe but often ineffective.
Partial DiGeorge syndrome permits age-appropriate inactivated vaccines; live vaccines considered if CD3+ >500/mm³ and CD8+ >200/mm³.

Chronic granulomatous disease contraindicates all live bacterial vaccines (Bacillus Calmette-Guérin [BCG], oral typhoid).
Live viral and inactivated vaccines safe and effective in phagocytic defects.
Complement deficiencies carry no vaccine contraindications.
Mandatory administration of Haemophilus influenzae type b (Hib), meningococcal, pneumococcal, and typhoid vaccines for complement defects.

Immunodeficiency	Contraindicated Vaccines	Recommended Vaccines
B-cell defects	All live vaccines	Annual IIV
T-cell defects (SCID)	All live viral and bacterial vaccines	IIV (often ineffective)
Complement deficiency	None	Hib, meningococcal, pneumococcal, typhoid
Phagocytic defects	Live bacterial vaccines	All inactivated and live viral vaccines

Vaccine safety and efficacy depend on immunosuppression degree.
OPV contraindicated in all cases; substitute with inactivated poliovirus vaccine (IPV).
Inactivated vaccines safe; antibody responses wane rapidly.

Vaccine	Asymptomatic HIV	Symptomatic HIV
BCG	Administer at birth	Contraindicated
DTwP/DTaP/Tdap	Routine schedule	Routine schedule
Polio	IPV preferred	IPV preferred
MMR	Administer at 9, 15 months, 5 years	Consider if CD4+ >15%
Varicella	Two doses	Consider if CD4+ >15%
Hepatitis B	Routine schedule	Double dose, four doses, titer check
Pneumococcal	PCV and PPSV23 indicated	PCV and PPSV23 indicated

High-dose systemic corticosteroids (prednisolone >2 mg/kg/day or >20 mg/day for >14 days) induce significant immunosuppression.
Live vaccines contraindicated during high-dose therapy.
Defer live vaccines until 1 month post-cessation of high-dose corticosteroids.
Low-dose, alternate-day, topical, intra-articular, or inhaled corticosteroids permit live vaccine administration.
Methotrexate (≤0.4 mg/kg/week) and azathioprine (≤3 mg/kg/day) do not contraindicate live vaccines.
Biologic response-modifying drugs require withholding live vaccines for 12 months post-discontinuation.
Re vaccinate the child if the child had a course of Rituximab
Administer inactivated vaccines 2 weeks prior to initiating biologics; live vaccines 4 weeks prior.

Chemotherapy causes major secondary immunodeficiency.
Live vaccines contraindicated during therapy and for 6 months post-chemotherapy.
Non-live vaccines deferred until 6 months post-treatment to ensure durable immunity.
Annual IIV recommended during ongoing chemotherapy.
Hepatitis B vaccine recommended for previously unimmunized children at risk of transfusion-transmitted infections.
Sibling contacts must avoid OPV; IPV substitution mandatory.
Postexposure rabies prophylaxis requires specific immunoglobulin and full vaccine course regardless of prior immunization.

Recipients lose memory immune responses post-ablation.
Inactivated vaccines (DTP, Hib, IPV, Hepatitis B, PCV) commence 6-12 months post-HSCT.
Administer annual IIV starting 6 months post-HSCT.
Live vaccines (MMR, Varicella) considered 24 months post-HSCT if immunocompetent and free of active graft-versus-host disease.

Greatest immune suppression occurs 3-6 months post-transplant.
Pre-transplant candidates must complete inactivated vaccines 2 weeks prior.
Live vaccines must be completed 4 weeks prior to transplant.
Post-transplant, recommence inactivated vaccines at 6 months when immunosuppression lowers.
Live vaccines generally contraindicated post-transplant.

High risk for overwhelming sepsis by encapsulated organisms.
Mandatory vaccines include pneumococcal (conjugate and polysaccharide), Hib, meningococcal, and typhoid.
Elective splenectomy requires completing vaccine schedules 2 weeks prior.
Emergency splenectomy permits vaccination prior to hospital discharge.
Live vaccines safely administered.