The investigators compare two strata of vaccinated patients: those recently vaccinated and those vaccinated more than two years ago. The primary objective is to compare pneumonia rates between the groups. As exploratory objectives, the investigators will describe the anti-pneumococcal antibody titers in hemodialysis patients as a function of time since vaccination, and determine factors influencing antibody kinetics. Further exploratory objectives investigate the relationship between antibody titers and the incidence of pneumonia in hemodialysis patients and extrapolate a possible cut-off for protection from pneumonia.

Participating sites will screen all hemodialysis patients at their outpatient dialysis clinic for eligibility. Eligible patients will be approached and informed by their treating physician. If a patient agrees to participate in the study and to sign an informed consent form, basic data regarding vaccination history, underlying disease, etc. will be entered or electronically imported into the study eCRF. Pneumococcal antibody titers will be drawn at baseline and every 3 months. For newly vaccinated patients baseline titers will be drawn 4 weeks after the vaccination. DZIF CTUs will coordinate titer assessment schedules and inform the participating physicians of upcoming blood samplings. The samples will be taken on dialysis days and thus constitute only a minimal additional burden for both patients and physicians. DZIF CTUs will actively follow up on study patients for 2 years after enrolment. This follow-up will include validation of all hospitalizations and deaths documented in an electronic registry database to assess whether the primary endpoint (pneumonia) occurred. Additionally, dialysis units will be contacted every 6 months to assess if pneumonia occurred, which did not require hospitalization. DZIF CTUs will document titer assessment results in the eCRF. Titers will not be disclosed to the attending physicians because revaccination due to knowledge of titers would produce bias. All therapies and diagnostics including vaccinations will be administered solely as part of clinical routine and as recommended by appropriate guidelines (e.g. RKI STIKO recommendations).

Inclusion Criteria:

• Signed informed consent form including enrolment in registry database (QiN-registry)
• Patients with stage 5 chronic kidney disease treated with chronic hemodialysis
• Patients who are either already vaccinated or eligible and willing to be vaccinated against pneumococcal infection in accordance with current STIKO recommendations
• Age of 18 years or older

Exclusion Criteria:

• Patients unwilling/ineligible for vaccination under current STIKO recommendations

Adult hemodialysis patients vaccinated against pneumococcal infection or eligible and willing to be vaccinated