Vaccination status and immune response to 13-valent pneumococcal conjugate vaccine in asplenic individuals.

Overwhelming post-splenectomy infection (OPSI) is immediately life-threatening and vaccination against encapsulated bacteria, in particular pneumococci, decreases its incidence. First, we investigated the adherence to vaccination guidelines in a retrospective study of the hospital records of splenectomised patients. Second, patients were asked to complete a questionnaire and invited to participate in a study where 12-valent pneumococcal serotype-specific IgG concentrations were determined before and 4 to 6 weeks after vaccination with PCV13. Of 79 individuals who underwent splenectomy between 2000 and 2012: 81.0% received pneumococcal vaccine, 51.9% received vaccine against Haemophilus influenzae type B and 22.8% received meningococcal vaccine. 31 individuals were deceased. 33 individuals completed questionnaires and accepted participation in the second part of the study. The participants consisted of two groups: (1) prior PPV23 (n=24) and (2) prior PPV23+PCV13 (n=9). In group 1, pre-PCV13 GMC's≥0.35μg/mL were observed for serotypes 1, 4, 6B, 7F, 9V, 14, 18C, 19A, 19F and 23F, and GMC's<0.35μg/mL for serotypes 3 and 5, significant increases pre- to post-PCV13 were found for serotypes 1, 3, 4, 5, 7F, 18C, 19A, 23F (p≤0.001) and 19F (p=0.01) and all 12 serotypes-specific GMC were above 0.35μg/mL after vaccination. Group 2 did not receive vaccine in this study, but blood tests showed all 12 serotype-specific GMC>0.35μg/mL. Adherence to guidelines regarding primary pneumococcal vaccination was adequate but only a minority received the recommended meningococcal vaccination. High levels of pneumococcal serotype-specific antibodies were observed in the previous PPV23 vaccinated group, and more pronounced in the previous PCV13 group, and our data suggests that PCV13 is immunogenic for serotypes 1, 3, 4, 5, 7F, 18C, 19A, 19F and 23F, if used as a booster dose in asplenic patients with previous PPV23 vaccination.