Post-COVID symptoms and their severity reported by patients during different infection waves in Germany

Declarations. Conflict of interest: The authors declare no competing interests. Ethical Approval and consent to participate: The Heinrich-Heine-University Düsseldorf’s Ethics Committee, as the leading ethics committee, approved the study protocol, informed consent forms, and participant information materials in November 2021 (under the study registration number 2021—1688). In addition, the Ethics Committee at each clinical research site approved the study. Participant informed consent: Participation in the study was voluntary and required comprehensive medical information about the meaning and purpose of the study, as well as the advantages and disadvantages of participating in the study and a signed declaration of consent. The study participant could revoke this consent in writing or verbally without giving reasons. In the event of a revocation, the study participant could decide whether the data collected for the study should be deleted, whether the samples obtained or the test results collected should be destroyed, or whether they can continue to be used for the study. The data and biomaterials collected during the study will be retained for a maximum of 10 years after completion of the study. The study participants had the opportunity to limit the use of data in the declaration of consent as part of the study information regarding other/future research purposes and time. Consent for publication: All authors have read and agreed to the published version of the manuscript. Study centres: The coordinator center is the Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital, Medical Faculty of Heinrich Heine University Düsseldorf, Germany. Further centers are the Department of Pneumology and Intensive Care Medicine, RWTH University Hospital, Aachen, Germany; Department of Medicine I, University Hospital Bonn, Germany; Department of Infectious Diseases; West German Centre of Infectious Diseases, University Hospital Essen, University of Duisburg-Essen, Essen, Germany; Department I of Internal Medicine, Faculty of Medicine and University Hospital, University of Cologne, Germany; Department of Internal Medicine B, Gastroenterology, Hepatology, Endocrinology and Clinical Infectiology, University Hospital Münster, Germany. Clinical trial registration: This study was registered in the German Clinical Trials Register under the Clinical trial number DRKS00027377 on 08.12.2021, accessible online at: https://drks.de/search/en/trial/DRKS00027377/details Data collection: Pseudonymized health data was collected by the study centers during each study visit on standardized case report forms (CRFs). This included demographic, clinical, and viro-immunological data. These health data were transferred into a clinical database system (Clincase, Quadratek Data Solutions Ltd., Berlin, Germany), administered by the Center for Clinical Studies Essen, Germany (ZKSE). Recording and health data transfer were subject to the consent of the study participants. Data collection procedures strictly adhere to the established protocol, the recent version of the Declaration of Helsinki, general data protection regulations of the European Union (EU-DSGVO), and the International Conference on Harmonization Good Clinical Practice (ICH-GCP). Data quality and plausibility checks were carried out by trained ZKSE employees. Complex plausibility checks were programmed in SAS. If necessary, queries were sent to members of the study teams at the centers to make corrections to the data. Data protection: The pseudonymously collected data is analyzed and evaluated for interim evaluations and finally for the legally required evaluations. All data in the study database can only be identified by a participant identification number (participant ID) corresponding to participant consent to ensure pseudonymization. The birth year is documented in the database, not the day and month. Only the local study centers maintain a separate confidential identification list to identify everyone enrolled to enable participants. This list is protected from unauthorized access stored in the respective study center. All persons who have access to pseudonymized data are subject to the general data protection regulations of the European Union (EU-DSGVO) when handling the data. Only anonymized data are passed on when the final study report is submitted to the responsible German authorities (higher federal authorities, ethics committees if applicable). Publications on the study will only be made with anonymous data. The data must be retained following legal requirements. An assessment of the necessity and proportionality of the data processing was obtained. A risk assessment regarding the possible risks caused by the processing for those affected is taken into account, and the protection goals of confidentiality, integrity, and availability were assessed. The remaining residual risk regarding the protection goals of integrity, legal control, availability, and confidentiality after implementation of technical and organizational measures are classified as low.