This clinical trial is focused on studying the effectiveness and safety of three different vaccine strategies for preventing infections caused by the bacteria *Neisseria meningitidis* group B in patients with *asplenia*. *Asplenia* is a condition where a person does not have a functioning spleen, which is an organ that helps fight infections. The vaccines being studied are *Bexsero* and *Trumenba*, both of which are designed to protect against *meningococcal* group B infections. *Bexsero* contains several components produced using recombinant DNA technology, which means they are made by combining DNA from different sources to create a new set of genes. *Trumenba* includes proteins from two subfamilies of the *Neisseria meningitidis* group B bacteria.

The purpose of the study is to assess how well these vaccines work in generating an immune response in adults with *asplenia*. Participants will receive the vaccines as injections into the muscle. The study will last for several months, with the main evaluation occurring one month after the completion of the vaccine series. During this time, researchers will monitor the participants to see how their immune systems respond to the vaccines and to ensure their safety.

Participants in the study will be adults who have been without a functioning spleen for at least two weeks. The study will help determine the best vaccination strategy for protecting people with *asplenia* from *meningococcal* group B infections, which can be serious and life-threatening. The results of this study could provide valuable information for improving the health and safety of individuals with this condition.