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 6 months post-discontinuation.
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.
🌱 This is a Digital Garden. Notes are always growing and changing.
These notes are intended for educational purposes only and reflect my personal understanding of the subject. Please cross-reference with standard textbooks and current clinical guidelines.
Authored by Dr. Rubanbalaji 2026
