Can a patient who underwent bone‑marrow (stem‑cell) transplantation receive routine vaccines, and what are the timing and restrictions for inactivated versus live‑attenuated vaccines?

Vaccination After Bone Marrow Transplantation

Patients who have undergone bone marrow (hematopoietic stem cell) transplantation cannot receive vaccines normally and must be considered as "never vaccinated," requiring complete revaccination on a specific delayed schedule that differs fundamentally from routine immunization. 1

Core Principle: Loss of Immunity

Antibody titers to all vaccine-preventable diseases (tetanus, poliovirus, measles, mumps, rubella, encapsulated bacteria) decline within 1-4 years after both allogeneic and autologous HSCT if revaccination does not occur. 1 This occurs regardless of pre-transplant vaccination status in either the donor or recipient. 2

Inactivated Vaccines: Timing and Schedule

Begin inactivated vaccines at 3-6 months post-transplant for most vaccines, with specific exceptions detailed below. 1, 2

Influenza Vaccine

• Start at ≥6 months post-HSCT and administer annually thereafter for life. 1
• Exception: During a community influenza outbreak, may administer as early as 3-4 months post-transplant (but never before 3 months). 1
• Children aged 6 months-8 years receiving influenza vaccine for the first time require 2 doses. 1

Pneumococcal Vaccines

• Administer 3 doses of PCV13 starting at 3-6 months post-HSCT, given at 1-month intervals. 1
• Follow with 1 dose of PPSV23 at 12 months post-HSCT, provided the patient does not have chronic graft-versus-host disease (GVHD). 1
• For patients with chronic GVHD at 12 months, consider a fourth dose of PCV13 instead of PPSV23. 1

Other Inactivated Vaccines (Starting 6-12 Months Post-HSCT)

• Haemophilus influenzae type b (Hib): 3-dose series at 6-12 months post-HSCT. 1
• Tetanus/diphtheria-containing vaccines: 3 doses starting at 6 months post-HSCT. For children <7 years, use DTaP; for patients ≥7 years, consider DTaP (preferred over Td/Tdap). 1
• Meningococcal (MCV4): 2 doses at 6-12 months post-HSCT for patients aged 11-18 years, with booster at age 16-18 if initial dose given at 11-15 years. 1
• Inactivated poliovirus (IPV): Include in standard revaccination schedule. 1

Live Attenuated Vaccines: Strict Restrictions

Live vaccines (MMR, varicella, zoster live) are contraindicated until ≥24 months post-transplant and only if ALL of the following conditions are met: 1

Absolute Requirements for Live Vaccine Administration

1. Minimum 24 months post-HSCT 1
2. No active chronic GVHD 1, 3
3. No ongoing immunosuppressive therapy 1, 3
4. Patient is presumed immunocompetent 1

Specific Live Vaccine Guidance

• MMR vaccine: Administer at 24 months post-HSCT if above criteria met. 1
• Varicella vaccine: Assess immune status case-by-case; if administered, give minimum 24 months post-HSCT when immunocompetent. 1
• Recombinant zoster vaccine (Shingrix): This is an inactivated vaccine and can be given starting at 6 months post-HSCT, making it the preferred zoster vaccine for HSCT recipients. 1
• Live attenuated influenza vaccine (LAIV): Permanently contraindicated in HSCT recipients. 1

Critical Contraindications and Timing Rules

Avoid Vaccination During These Periods

• First 2-3 months post-transplant: All vaccines should be withheld due to inadequate immune response. 1
• During intensified immunosuppression: Defer vaccination until immunosuppression is reduced. 1
• Active acute GVHD: While not an absolute contraindication for inactivated vaccines, response may be suboptimal. 2

Chronic GVHD Considerations

Patients with chronic GVHD have higher infection risk and should still receive inactivated vaccines starting at 3-6 months post-HSCT, as they are likely to benefit despite potentially reduced response. 2 However, chronic GVHD is an absolute contraindication to live vaccines. 1, 3

Pre-Transplant Vaccination Strategy

HSCT candidates should receive all age-appropriate vaccines before transplant if not already immunosuppressed, with specific timing requirements: 1

• Live vaccines: Must be given ≥4 weeks before starting the conditioning regimen. 1
• Inactivated vaccines: Must be given ≥2 weeks before starting the conditioning regimen. 1
• Varicella vaccine: Non-immune candidates aged ≥12 months should receive 2-dose regimen if sufficient time allows and patient is not immunosuppressed. 1

Household Contact Vaccination

All household contacts and healthcare workers caring for HSCT recipients must be appropriately vaccinated, including against influenza, measles, and varicella. 1 This creates a protective cocoon around the immunocompromised patient. Contacts should receive all age-appropriate vaccines, with the historical exception of oral poliovirus vaccine (OPV, no longer used in the US) and smallpox vaccine. 1

Common Pitfalls to Avoid

1. Do not assume pre-transplant immunity persists: Even if the patient or donor was fully vaccinated before transplant, immunity is lost and complete revaccination is required. 1, 2

2. Do not give live vaccines before 24 months or in patients with GVHD: This can cause severe vaccine-induced disease due to suppressed T-cell immunity. 1

3. Do not delay inactivated vaccines waiting for "better" immune function: Starting at 3-6 months captures a window where response is adequate and infection risk is high. 2

4. Do not withhold vaccination due to concern about GVHD exacerbation: No evidence suggests inactivated vaccines trigger or worsen GVHD. 1, 2

5. Do not confuse recombinant zoster vaccine (inactivated) with live zoster vaccine: Recombinant vaccine (Shingrix) can be given at 6 months post-HSCT; live vaccine (Zostavax) requires 24 months and no GVHD. 1