Which vaccinations are indicated after splenectomy?

Asplenic individuals are known to be at an elevated risk for infection with encapsulated bacteria. The lifetime, risk of post-splenectomy sepsis is estimated to be approximately 1% to 2%. The overwhelming majority of these cases are caused by Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitides. In 2 recent RCTs, the 23-valent pneumococcal polysaccharide vaccine was tested on patients 1, 7, 14, and 28 days after splenectomy. The studies demonstrated that the immunogenicity of the vaccine was best when given at or after day 14 after the operation. In both studies, patients immunized at day 14 had immunoglobulin G (IgG) antibody levels approaching those of control subjects with intact spleens. There were no differences in antibody levels among those patients immunized at day 14 compared with those immunized on day 28. However, those subjects immunized on days 1 and 7 had significant lower antibody levels than the control subjects or those immunized on day 14. In another study, 130 asplenic individuals were compared with 48 age-matched controls after receiving a meningococcal vaccine. 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. 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.