The COVIDOUT study will prospectively investigate the serological immunity of outpatient cancer patients to evaluate the prevalence of previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and dependency of serological immunity on systemic (chemo)therapy after COVID19 disease as well as after vaccination.

In this prospective observational study all cancer patients who are regularly treated in the Oncology Outpatient Clinic of the University Medical Center Hamburg-Eppendorf (UKE) will be included in the study upon consent.

Data will be collected as follows:

(i) Serological antibody screening at study inclusion and every 3 months (ia) In case of vaccination monthly screening for 3 months (ii) Routine clinical data: demographic and biometric data, medical history, common laboratory parameters (iii) Patient questionnaire: assessment of past COVID-19 infection, past COVID-19 specific symptoms, social environment, vaccination

Recruitment is limited to a one-year period (December 2020 - December 2021)

Inclusion Criteria:

• Known diagnosis of cancer
• Active disease or (in case of cure) last systemic therapy <12 months
• Signed informed consent

Exclusion Criteria:

• Refusal of participation

The study population consists of cancer patients who are regularly treated in the Oncology Outpatient Clinic of the University Medical Center Hamburg-Eppendorf (UKE)

Aggregated data will be shared