What vaccinations are recommended before undergoing splenic artery embolization?

Vaccination Recommendations Before Splenic Artery Embolization

Patients undergoing splenic artery embolization who lose ≥50% of splenic mass should receive the same vaccination protocol as splenectomy patients: pneumococcal (PCV followed by PPSV23), meningococcal (MenACWY and MenB), Haemophilus influenzae type b, and annual influenza vaccines. 1, 2

Determining Need for Vaccination

The critical threshold is 50% or more splenic mass loss—these patients must be treated as functionally asplenic and require full vaccination 3. Review angiographic imaging post-procedure to estimate the proportion of spleen embolized 3.

• Patients with <50% embolization do not require post-splenectomy vaccinations 3
• However, clinical judgment should prevail if there is concern about splenic function 4

Optimal Vaccination Timing

For planned/elective procedures: Administer all vaccines at least 2 weeks before embolization (ideally 4-6 weeks if possible) to ensure optimal antibody response 1, 2. Antibody formation generally takes 9 days, making the 2-week minimum critical 4.

For emergency/trauma cases: Wait at least 14 days post-procedure before vaccinating, as antibody response is suboptimal before this timeframe 1, 2. If vaccination occurs earlier than 14 days post-operatively, it yields insufficient antibody response 4.

Required Vaccines and Administration Schedule

Pneumococcal Vaccination

• First: PCV20 (preferred) or PCV15 as initial vaccine 1
• Second: If using PCV15, follow with PPSV23 at least 8 weeks later 1, 2
• Revaccination: PPSV23 every 5 years for life 1, 2

For patients previously vaccinated with PCV13 only, give PCV20 at least 1 year later 1.

Meningococcal Vaccination

• MenACWY: 2 doses given 8 weeks apart 1, 2
• MenB: 2-3 dose series depending on formulation 1, 2
• Revaccination: MenACWY every 5 years for life; MenB every 2-3 years if risk remains 1, 2

The risk of meningococcal infection carries 40-70% mortality in asplenic patients, making this vaccination essential 4.

Haemophilus Influenzae Type B (Hib)

• Single dose for previously unvaccinated adults 1, 2
• No revaccination needed if patient received primary series in childhood 4

Influenza

• Annual inactivated or recombinant influenza vaccine for life 1, 5
• While asplenic patients don't have higher influenza risk, the vaccine reduces secondary bacterial pneumonia and sepsis risk by 54% 4

Critical Pitfalls to Avoid

The most common error is failing to vaccinate patients with ≥50% embolization. Research shows only 8% of splenic embolization patients receive appropriate immunizations, and none receive recommended boosters 3. This represents a major gap in care.

Do not forget lifelong revaccination schedules:

• PPSV23 every 5 years 1, 2
• MenACWY every 5 years 1, 2
• MenB every 2-3 years 1
• Annual influenza 1, 5

Avoid vaccinating patients with <50% embolization—three of four patients in one study were incorrectly vaccinated when they had preserved splenic function 3.

Special Considerations

Patients on rituximab: If rituximab was given within the previous 6 months, vaccine response will be suboptimal 1. Reassess vaccination timing once B-cell recovery occurs 1.

All vaccines can be administered simultaneously at different injection sites 4.

Additional Protective Measures Beyond Vaccination

• Lifelong antibiotic prophylaxis with phenoxymethylpenicillin, especially in first 2 years 1, 2
• Emergency standby antibiotics (amoxicillin) at home for immediate use with fever >101°F (38°C) 1, 2
• Medical alert identification and formal notification to primary care providers of asplenic status 2, 5
• Special precautions for dog bites: 5-day course of co-amoxiclav due to Capnocytophaga canimorsus susceptibility 1, 5

The Stakes: Why This Matters

Overwhelming post-splenectomy infection (OPSI) carries 30-70% mortality, with most deaths occurring within 24 hours 2, 5. The risk is lifelong, with cases reported more than 20 years post-procedure 1. Streptococcus pneumoniae accounts for approximately 50% of OPSI cases 1. Proper vaccination could prevent at least 28% of invasive bacterial infections in this population 6.

Despite these risks, vaccination coverage remains suboptimal: only 55% receive pneumococcal vaccine, 48% receive Hib, 34% receive meningococcal ACWY, and 13% receive meningococcal B 7. Healthcare providers must implement specific prophylaxis protocols to guarantee better immunization compliance 7.