Could a Two-Vaccine strategy better shield spleenless patients from pneumonia?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age ≥ 18 years 2. Splenectomised patients. 3. For patients not enrolled in SPLENEVAC clinical trial: presence of Jolly Body at blood smear and spelenectomy confirmation by abdominal ultrasound. 4. Vaccinated according to the schedule of SPLENEVAC clinical trial (PCV13 / PPS23 two months later (until +4 months)), enrolled or not from this study. Vaccination of PPS23 must have been administered 5 years - 6 months/+ 1 year before inclusion. 5. Patients will be followed during the 24 months from the inclusion visit. 6. Patients must give written informed consent prior to any trial procedure. 7. Women of childbearing age must have an effective contraception during the first 13 months of the study. 8. Patients must be covered by social security regimen or equivalent. Exclusion Criteria: 1. History of pneumococcal revaccination in the last five years. 2. Having received any another vaccines within 4 weeks prior to enrolment or who is planning to receive any vaccine (for example: ZOSTAVAX®) within the first 13 months of the study (excepted seasonal influenza vaccine which is permitted 4 weeks before and after each vaccination visit of the study and then allowed at any time during the study follow up. Furthermore, the vaccination against Sars-CoV-2 is allowed during the study with a minimum interval of 14 days between pneumococcal vaccine and Sars-Cov-2 vaccine injection) 3. History of known allergies to any component of both study vaccines (active substances, excipients or diphtheria toxoid). 4. History of anaphylactic reaction following vaccination. 5. Infusion of immunoglobulins within the three months preceding the inclusion. 6. Any pathology or condition that may impair the immune response, apart from splenectomy: immunosuppressive therapy in progress or in the 6 months prior to inclusion, hematopoietic stem cells allo / autograft, primary immunodeficiency, nephrotic syndrome, progressive neoplasia, evolutive cancer, cirrhosis, known infection to HIV and / or hepatitis B virus (HBV) (HBs Ag +) and / or hepatitis C virus (HCV), taking corticosteroids \> 10mg for more than 14 days within the month preceding the inclusion , inhaled corticosteroid and cutaneous topical being allowed. 7. Coagulation disorder contra-indicating intramuscularly injections. 8. Acute respiratory tract infection or severe acute febrile illness or systemic reaction which could represent a significant risk in case of vaccination within the month before inclusion. 9. Pregnancy, breastfeeding or positive pregnancy test up to 13 months after inclusion. 10. History of suspected or documented invasive pneumococcal infection within the year before inclusion. 11. Immunosuppressive factors associated. 12. Enrolment in any other clinical trial during the whole trial period except observational study. 13. Adults under protection