{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T10:41:44Z","timestamp":1773916904578,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T00:00:00Z","timestamp":1773705600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"German Federal Ministry of Health"},{"DOI":"10.13039\/501100000805","name":"European Centre for Disease Prevention and Control","doi-asserted-by":"publisher","award":["2021\/008 ECD.12222"],"award-info":[{"award-number":["2021\/008 ECD.12222"]}],"id":[{"id":"10.13039\/501100000805","id-type":"DOI","asserted-by":"publisher"}]},{"name":"European Union\u2019s EU4Health program","award":["101113012 within the IMS-HERA2 project"],"award-info":[{"award-number":["101113012 within the IMS-HERA2 project"]}]},{"DOI":"10.13039\/100020655","name":"European Health and Digital Executive Agency","doi-asserted-by":"crossref","award":["101113012"],"award-info":[{"award-number":["101113012"]}],"id":[{"id":"10.13039\/100020655","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Nosocomial outbreaks of viral respiratory infections strain healthcare systems and endanger patients and healthcare workers (HCWs). We describe two large nosocomial outbreaks with the SARS-CoV-2 Alpha variant, during its initial emergence in Germany, to assess transmission dynamics, effectiveness of control measures, and challenges in managing highly transmissible respiratory viruses. Methods: Confirmed cases were inpatients, HCWs, or their contacts testing SARS-CoV-2-positive since 1 January 2021 (Hospital A [HA])) or 21 January 2021 (Hospital B [HB])) with N501Y and delH69\/V70 spike gene mutations. We conducted case interviews, reviewed medical records and shift schedules, and performed sequencing, genome reconstruction, and phylogenetic analysis. We describe cases, transmission chains, and control measures. Results: HA reported 18 patient cases, 20 HCW cases, and 33 community cases (N = 71). HB reported 48 patient cases, 43 HCW cases (13 in a COVID-19 ward), and 27 community cases (N = 118). In-hospital transmission occurred patient-to-patient, HCW-to-patient, patient-to-HCW, and HCW-to-HCW. HA halted admissions immediately after the initial cases; HB implemented measures gradually. Regular testing detected pre-symptomatic (HA = 6; HB = 18) and asymptomatic cases (HA = 3; HB = 13). Testing of agency staff was incomplete. The suspected primary case was an HCW in HA and a patient in HB who required resuscitation shortly after admission. Conclusions: Early COVID-19 outbreaks offer valuable lessons for managing emerging nosocomial outbreaks of highly transmissible respiratory viruses. Our findings provide empirical evidence for effective interventions, including rapid response, testing, HCW protection, and rigorous contact tracing in high-risk emergency situations. Managing agency staff remains a major challenge.<\/jats:p>","DOI":"10.3390\/jcm15062290","type":"journal-article","created":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T12:42:16Z","timestamp":1773751336000},"page":"2290","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Lessons from Two Early COVID-19 Hospital Outbreaks in Germany to Inform Strategies for Controlling Emerging Nosocomial Outbreaks of Highly Transmissible Respiratory Viruses"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-5663-8532","authenticated-orcid":false,"given":"Sofia","family":"Burdi","sequence":"first","affiliation":[{"name":"Department of Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany"},{"name":"Postgraduate Training for Applied Epidemiology (PAE), Department of Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany"},{"name":"European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), 16973 Stockholm, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3205-3513","authenticated-orcid":false,"given":"Felix","family":"Reichert","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barbara","family":"M\u00fchlemann","sequence":"additional","affiliation":[{"name":"National Consultant Laboratory for Coronaviruses, 10117 Berlin, Germany"},{"name":"Institute of Virology, Charit\u00e9 Universit\u00e4tsmedizin, 10117 Berlin, Germany"},{"name":"German Centre for Infection Research (DZIF), Partner Site Charit\u00e9, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3605-0136","authenticated-orcid":false,"given":"Victor M.","family":"Corman","sequence":"additional","affiliation":[{"name":"National Consultant Laboratory for Coronaviruses, 10117 Berlin, Germany"},{"name":"Institute of Virology, Charit\u00e9 Universit\u00e4tsmedizin, 10117 Berlin, Germany"},{"name":"German Centre for Infection Research (DZIF), Partner Site Charit\u00e9, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1120-9531","authenticated-orcid":false,"given":"Terry C.","family":"Jones","sequence":"additional","affiliation":[{"name":"National Consultant Laboratory for Coronaviruses, 10117 Berlin, Germany"},{"name":"Institute of Virology, Charit\u00e9 Universit\u00e4tsmedizin, 10117 Berlin, Germany"},{"name":"German Centre for Infection Research (DZIF), Partner Site Charit\u00e9, 10117 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin","family":"H\u00f6lzer","sequence":"additional","affiliation":[{"name":"Genome Competence Center, Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Susanne B.","family":"Schink","sequence":"additional","affiliation":[{"name":"Department of Infectious Disease Epidemiology, Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Patrick","family":"Larscheid","sequence":"additional","affiliation":[{"name":"Local Public Health Agency Reinickendorf, 13407 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jakob","family":"Schumacher","sequence":"additional","affiliation":[{"name":"Local Public Health Agency Reinickendorf, 13407 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gudrun","family":"Widders","sequence":"additional","affiliation":[{"name":"Local Public Health Agency Spandau, 13597 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Inas","family":"Abdelgawad","sequence":"additional","affiliation":[{"name":"Local Public Health Agency Spandau, 13597 Berlin, Germany"},{"name":"Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Cairo University, Al Kasr Al Aini, Cairo 4240310, Egypt"},{"name":"Public Health Authority Havelland, 14712 Brandenburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christian","family":"Brandt","sequence":"additional","affiliation":[{"name":"Institute for Hygiene and Environmental Medicine, Vivantes Hospital, 13407 Berlin, Germany"},{"name":"Centre of Infectious Diseases, Medical Microbiology and Hygiene, Medical Faculty Heidelberg, 69120 Heidelberg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicole","family":"Dinsel","sequence":"additional","affiliation":[{"name":"Institute for Hygiene and Environmental Medicine, Vivantes Hospital, 13407 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katharina","family":"Jelavic","sequence":"additional","affiliation":[{"name":"Institute for Hygiene and Environmental Medicine, Vivantes Hospital, 13407 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nadine","family":"Kurzke","sequence":"additional","affiliation":[{"name":"Institute for Hygiene and Environmental Medicine, Vivantes Hospital, 13407 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J\u00f6rg","family":"Hofmann","sequence":"additional","affiliation":[{"name":"Institute of Virology, Charit\u00e9 Universit\u00e4tsmedizin, 10117 Berlin, Germany"},{"name":"Labor Berlin-Charit\u00e9 Vivantes, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6227-3125","authenticated-orcid":false,"given":"Janine","family":"Michel","sequence":"additional","affiliation":[{"name":"Center for Biological Threats and Special Pathogens 1 (ZBS 1), Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Annika","family":"Brinkmann","sequence":"additional","affiliation":[{"name":"Center for Biological Threats and Special Pathogens 1 (ZBS 1), Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stephan","family":"Fuchs","sequence":"additional","affiliation":[{"name":"Genome Competence Center, Robert Koch Institute, 13353 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christian","family":"Drosten","sequence":"additional","affiliation":[{"name":"National Consultant Laboratory for Coronaviruses, 10117 Berlin, 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