This observational study aims to collect standardized clinical data and biosamples from adults in university hospitals across Germany. The main goals are to create a cohort that combines clinical data, pathogen samples, and biosamples, with consent for future research. A pre-screening program tracks infection-related hospitalizations, helping detect pathogen changes early and respond quickly. Participants will be recruited if they have respiratory, bloodstream, gastrointestinal, emerging, or central nervous system infections. Data and biosamples will be collected at the start and end of the hospital stay, with additional visits if needed.

As part of the European concept of ever-warm recruiting infrastructures in case of future public health hazards, but also as instrument for answering pressing questions in the field of major infectious diseases, the cohort of the Specialist Network Infectious Diseases (SNID) collects clinical patient data and biosamples in a standardized and quality-assured manner. In this sense, the SNID manifests itself as a structured data and decentralized biobank within the German Network University Medicine (NUM).

The main objectives of the SNID cohort are: 1) To collect clinical patient data and biosamples from major infectious diseases to accelerate translational and outcomes research with the aim of improving diagnosis and treatment strategies for future patients, 2) To establish pandemic preparedness by initiating and maintaining an ever-warm recruitment network in the field of infectious diseases, 3) To establish a sentinel programme to observe and monitor outbreaks of severe infections requiring hospitalization of patients.

The study will identify and recruit patients across different specific modules, each providing a sub-protocol to this master study protocol. These modules focus on major areas of infectious diseases ("entities") and will describe research questions and priorities as well as specific requirements for the observation of the respective affected patients. They will also denominate specific sub-types ("sub-entities") of these diseases that are or may become a focus of the SNID cohort. As an example, the module "respiratory infections" may have an entity "community-acquired pneumonia" that in turn may have sub-entities like "community-acquired pneumonia caused by legionella pneumophila".

A base of sociodemographic, epidemiologic, and clinical patient data is documented, including information on possible pre-existing conditions, medical diagnoses, and therapies.

The documentation is supplemented by residual or non-invasive biosampling, depending on the study tier. Three different tiers establish different levels of sampling and data collection in terms of frequency or depth of assessment. The Tiers have been adapted mainly from the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC).

Tier 2: Serial collection of data and biosamples (additional non-invasive collection of biosamples and residual samples) at the baseline visit, once a week starting on day 3 until the final visit (corresponding to tier 2, sampling schedule 4 by ISARIC).

Tier 1: Collection of data and biosamples (additional non-invasive collection of biosamples and residual samples) at baseline visit and final visit (corresponding to tier 1 by ISARIC).

Tier 0: Only documentation of data and preservation of residual samples (routine clinical care) at baseline visit and final visit (corresponding to tier 0 by ISARIC).

For tier 1 and 2, additional non-invasive biosamples may be collected as part of the study. Non-invasive is defined as no new tissue penetration or other harm to the patient, allowing for swabbing, collection of spontaneously ejectable fluids/substances, or usage of permanent devices or non-invasive access to materials.

Inclusion Criteria:

• Fulfillment of all inclusion and no exclusion criteria for at least one module
• Ability to perform all baseline visit data and biosample collections according to the study requirements no later than 48 hours (with an additional 48-hour period for weekends) after fulfilling all study and specific module inclusion and exclusion criteria
• Signed informed consent form from all patients capable of giving consent and understanding all contents of the informed consent
• Age ≥ 18 years.

Exclusion Criteria:

There are no generic exclusion criteria in the master study protocol.

Patients with defined clinical characteristics or presentations/pathogens are included at all participating study sites. Specific clinical characteristics or presentations/pathogens of interest are defined in the specific modules. Based on this master study protocol and the modules, the study teams will identify patients who meet all inclusion and none of the exclusion criteria and will inform them about the study and its objectives. Patients providing written IC will be included in the study.