Vaccination Considerations for the Asplenic Patient

Asplenic patients who contract encapsulated bacterial infections are vulnerable, so pharmacists should step forward to educate this population about complete vaccination coverage.

Individuals who have intact spleens respond to mundane pneumococcal, meningococcal, and Haemophilus influenzae B (Hib) infection bacteria and can eliminate them.

Depending on age, comorbidities, and other demographics, asplenic patients may develop meningitis or disseminated intravascular coagulation and can die from these conditions.

Asplenic patients can be protected by an array of immunizations, but the sheer number of products and complicated dosing schedules prevents widespread vaccination.

The American Journal of Health-System Pharmacists recently published a study reviewing vaccination recommendations for asplenic patients.

Patients may have a splenectomy due to trauma, hypersplenism, hereditary spherocytosis, immune thrombocytopenic purpura, or sickle cell disease. The case-specific benefit must be weighed against the loss of erythrocyte filtration, immunoglobulin M production, and encapsulated bacteria opsonization.

Overwhelming postsplenectomy infection (OPSI) involves encapsulated bacterial septicemia or meningitis after elective or emergent spleen removal. One in 20 patients will develop OPSI, and half of OPSI patients will die.

Pharmacists should advise asplenic adult patients to receive a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) and up to 3 doses of 23-valent pneumococcal polysaccharide vaccine (PPSV23), with 2 doses given before 64 years and a third dose after 65 years.

PCV13 strains account for 50% of infections, and PPSV23 cover 71% of infection strains. PPSV23 doses should be spaced at least 8 weeks apart, PPSV23 should be given at least 8 weeks after PCV13, and PCV13 should be given at least 1 year after PPSV23.

Inactivated influenza vaccination decreases pneumococcal mortality by 54%, but live-attenuated influenza vaccines are not recommended because of their lack of evidence in asplenic patients.

Invasive meningococcal infections are rare in the United States, but 10 to 15% of cases are fatal, and asplenic patients die in 40 to 70% of cases. Around 20% of survivors have serious sequelae.

Two distinct meningococcal vaccines by serotype are now available: ACWY conjugate vaccine (MenACWY-D/CRM) and B.

Two doses of MenACWY should be administered at least 2 months apart, with booster doses given every 5 years afterward. MenACWY-D reduces the effectiveness of PCV13 when given concomitantly, so defer MenACWY-D for at least 4 weeks.

The B serotype vaccines were approved in 2015 to be given in a 3-dose series (MenB-FHbp at 0-, 2-, and 6-month intervals) or a 2-dose series (MenB-4C at least 1 month apart) to all asplenic adults. The 2 doses of MenACWY and MenB-4C can be given concomitantly for convenience.

Invasive Hib disease has decreased by 98% since vaccination campaigns began in the 1990s and is rarely seen in adults with an intact spleen. Asplenic patients are considered immune if they received their pediatric immunizations, but vaccination is recommended if vaccination history is unknown or negative.

The study authors recommended providing needed vaccines 2 weeks prior to elective splenectomy when possible and 2 weeks after surgery otherwise. Pharmacists can counsel asplenic patients on the importance of these vaccines and provide the vaccinations depending on jurisdiction and setting.