This clinical trial studies immune responses to pneumococcal vaccines in people without a spleen (a condition called asplenia). The study compares two vaccines: Prevenar 20 and CAPVAXIVE, which are designed to protect against different strains of bacteria that can cause serious infections. The purpose is to understand how the timing of vaccination – either before or after surgical removal of the spleen – affects the body’s immune response to these vaccines.
The study involves adults who either have already had their spleen removed or are scheduled for spleen removal surgery. Participants will receive two different vaccines: first Prevenar 20, followed by CAPVAXIVE at least 12 months later. Both vaccines are given as a single injection into the muscle. The main focus is on measuring how well the immune system responds to the vaccines when given at different times relative to spleen removal.
The research team will collect blood samples to measure antibody levels and immune cell responses at various points during the study. This will help determine the best timing for vaccination in patients without a spleen. The study will continue for approximately two years, comparing immune responses between patients vaccinated before spleen removal, after spleen removal, and healthy individuals who still have their spleen.
The Netherlands 