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.
Primary Immunodeficiency Disorders
Vaccine administration depends upon specific immune compartment defects.
B-Lymphocyte 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.
T-Lymphocyte Defects
- 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.
Phagocytic And Complement Defects
- 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 |
Secondary Immunodeficiencies
Human Immunodeficiency Virus Infection
- 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 |
Corticosteroid And Immunosuppressive Therapy
- 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.
Cancer And Chemotherapy
- 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.
Hematopoietic Stem Cell Transplants
- 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.
Solid Organ Transplants
- 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.
Asplenia And Hyposplenia
- 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.