**5. Conclusions**

Healthcare-associated infections are common in critically ill COVID-19 patients treated in ICUs. Our study highlighted the importance of the type of intensive care treatment when it came to nosocomial infections. Patients receiving invasive ventilation had markedly increased rates of secondary bacterial and fungal infections compared with those receiving non-invasive treatment. Another distinct increase in infection rates was documented in ECMO-treated patients. This knowledge should inform future treatment decisions in the ICU.

**Author Contributions:** Conceptualization, S.B., D.E. and J.S.; methodology, S.B. and J.S.; validation, M.L.d.H., D.E. and J.S.; formal analysis, M.L.d.H. and J.S.; investigation, M.L.d.H., D.E. and J.S.; data curation, S.B., S.R., J.J.V., C.D.S., C.E.M.K., M.H., M.S. and F.H.; writing—original draft preparation, J.S.; writing—review and editing, M.L.d.H., S.B. and D.E.; visualization, M.L.d.H.; supervision, J.S.; project administration, J.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** The LEOSS registry is supported by the German Center for Infection Research (DZIF) and the Willy Robert Pitzer Foundation.

**Institutional Review Board Statement:** The study was conducted in accordance with the Declaration of Helsinki. Approval for LEOSS was obtained from the applicable local ethics committees of all participating centers and registered at the German Clinical Trails Register (DRKS, No. S00021145).

**Informed Consent Statement:** Patient consent was waived, as the study was based on a Scientific Use File (SUF) generated from the Lean European Open Survey on SARS-CoV-2-Infected Patients (LEOSS) registry. For the LEOSS database, data collection was performed fully anonymized, only once per case, and retrospectively after treatment was finished or the patient had died.

**Data Availability Statement:** Patient data from the LEOSS registry are subject to the LEOSS governance, data use, and access policy (policy text available on https://leoss.net; accessed on 4 August 2022).

**Acknowledgments:** We express our deep gratitude to all the study teams supporting the LEOSS study. The LEOSS study group contributed at least 5 per million to the analyses of this study from: University Hospital Regensburg (Frank Hanses), University Hospital Freiburg (Siegbert Rieg), Technical University of Munich (Christoph Spinner), Hospital Ingolstadt (Stefan Borgmann), Klinikum Dortmund gGmbH, Hospital of University Witten/Herdecke (Martin Hower), University Hospital Frankfurt (Maria Vehreschild), University Hospital Wuerzburg (Nora Isberner), University Hospital Tuebingen (Siri Göpel), Hospital Maria Hilf GmbH Moenchengladbach (Juergen vom Dahl), University Hospital Augsburg (Christoph Roemmele), University Hospital Jena (Maria Madeleine Ruethrich), University Hospital Cologne (Norma Jung), University Hospital Erlangen (Richard Strauss), University Hospital Ulm (Beate Gruener), Hospital Bremen-Center (Christian Hohmann), Hospital Ernst von Bergmann (Lukas Tometten), Hospital Passau (Julia Lanznaster), University Hospital Saarland (Robert Bals), Municipal Hospital Karlsruhe (Christian Degenhardt), University Hospital Duesseldorf (Bjoern-Erik Jensen), University Hospital Heidelberg (Uta Merle), Johannes Wesling Hospital Minden Ruhr University Bochum (Kai Wille), University Hospital Dresden (Katja de With), Bundeswehr Hospital Koblenz (Dominic Rauschning), University Hospital of Giessen and

Marburg (Janina Trauth), University Hospital Essen (Sebastian Dolff), University Hospital Schleswig-Holstein Kiel (Anette Friedrichs), Elbland Hospital Riesa (Joerg Schubert), Malteser Hospital St. Franziskus Flensburg (Milena Milovanovic), Marien Hospital Herne Ruhr University Bochum (Timm Westhoff), Clinic Munich (Wolfgang Guggemos), Catholic Hospital Bochum (St. Josef Hospital) Ruhr University Bochum (Kerstin Hellwig), Practice for general medicine Drs. Elisabeth Schroedter & Gabriele Mueller-Joerger Kuenzelsau (Gabriele Mueller-Joerger), Hospital Universitari Arnau de Vilanova (Juan Antonio Schoenenberger-Arnaiz), Hospital Braunschweig (Jan Kielstein), Hospital Leverkusen (Lukas Eberwein), University Hospital Munich/ LMU (Michael von Bergwelt-Baildon), Agaplesion Diakonie Hospital Rotenburg (David Heigener), Thorax University Hospital Heidelberg (Felix Herth), and Evangelisches Hospital Saarbruecken (Mark Neufang). The LEOSS study infrastructure group includes: Jörg Janne Vehreschild (Goethe University Frankfurt), Susana M. Nunes de Miranda (University Hospital of Cologne), Carolin E. M. Koll (University Hospital of Cologne), Melanie Stecher (University Hospital of Cologne), Lisa Pilgram (Goethe University Frankfurt), Nick Schulze (University Hospital of Cologne), Sandra Fuhrmann (University Hospital of Cologne), Annika Claßen (University Hospital of Cologne), Bernd Franke (University Hospital of Cologne), and Fabian Praßer (Charité, Universitätsmedizin Berlin).

**Conflicts of Interest:** The authors declare no conflict of interest.
