In another study, 130 asplenic individuals were compared with 48 age-matched controls after receiving a meningococcal vaccine.3 The majority (93%) achieved bactericidal immunoglobulin levels following immunization. This study demonstrated the need to have antibody titers drawn to ensure immunization response, as 20% of the subjects required a second dose of vaccine to achieve adequate levels. No clear evidence supports the timing of the meningococcal vaccine post-splenectomy.
Two recent studies look at the immunogenicity of the Hib for asplenic patients. The first study demonstrated increased antibody titers to Hib at 2, 6, 12, 24, and 36 months after immunization.4 Fifty of the 57 patients in the study (88%) maintained adequate antibody titers 3 years after immunization. No symptomatic infections were observed during the 3-year study period. In a study of 561 Danes, those vaccinated within 14 days of splenectomy (before or after) had a significantly higher need for revaccination than those who were vaccinated more than 14 days before or after surgery.5
Recommendations from others
The most common infections occurring among asplenic patients are due to encapsulated organisms. The incidence is 10 to 50 times higher than in the general population.
The Advisory Committee on Immunization Practices for the Centers for Disease Control and Prevention (CDC) and the Society of Surgery for the Alimentary Tract recommends all patients that undergo splenectomy have the pneumococcal polysaccharide vaccine.6-7 In addition, this organization also recommends that all asplenic patients receive meningococcal vaccination and be considered for the Hib vaccine. Both groups recommend that these vaccinations occur at the same time as the pneumococcal vaccine.6-8
The CDC also recommends annual influenza vaccine in addition to the pneumococcal, meningococcal, and Hib vaccines, because secondary bacterial infections can lead to severe disease in this patient population. Boosters are recommended for all the bacterial vaccines every 5 years for asplenic patients.