Integrated genomic surveillance enables tracing of person-to-person SARS-CoV-2 transmission chains during community transmission and reveals extensive onward transmission of travel-imported infections, Germany, June to July 2021.

BackgroundTracking person-to-person SARS-CoV-2 transmission in the population is important to understand the epidemiology of community transmission and may contribute to the containment of SARS-CoV-2. Neither contact tracing nor genomic surveillance alone, however, are typically sufficient to achieve this objective.AimWe demonstrate the successful application of the integrated genomic surveillance (IGS) system of the German city of Düsseldorf for tracing SARS-CoV-2 transmission chains in the population as well as detecting and investigating travel-associated SARS-CoV-2 infection clusters.MethodsGenomic surveillance, phylogenetic analysis, and structured case interviews were integrated to elucidate two genetically defined clusters of SARS-CoV-2 isolates detected by IGS in Düsseldorf in July 2021.ResultsCluster 1 (n = 67 Düsseldorf cases) and Cluster 2 (n = 36) were detected in a surveillance dataset of 518 high-quality SARS-CoV-2 genomes from Düsseldorf (53% of total cases, sampled mid-June to July 2021). Cluster 1 could be traced back to a complex pattern of transmission in nightlife venues following a putative importation by a SARS-CoV-2-infected return traveller (IP) in late June; 28 SARS-CoV-2 cases could be epidemiologically directly linked to IP. Supported by viral genome data from Spain, Cluster 2 was shown to represent multiple independent introduction events of a viral strain circulating in Catalonia and other European countries, followed by diffuse community transmission in Düsseldorf.ConclusionIGS enabled high-resolution tracing of SARS-CoV-2 transmission in an internationally connected city during community transmission and provided infection chain-level evidence of the downstream propagation of travel-imported SARS-CoV-2 cases.

Characterization of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection Clusters Based on Integrated Genomic Surveillance, Outbreak Analysis and Contact Tracing in an Urban Setting.

BACKGROUND: Tracing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission chains is still a major challenge for public health authorities, when incidental contacts are not recalled or are not perceived as potential risk contacts. Viral sequencing can address key questions about SARS-CoV-2 evolution and may support reconstruction of viral transmission networks by integration of molecular epidemiology into classical contact tracing. METHODS: In collaboration with local public health authorities, we set up an integrated system of genomic surveillance in an urban setting, combining a) viral surveillance sequencing, b) genetically based identification of infection clusters in the population, c) integration of public health authority contact tracing data, and d) a user-friendly dashboard application as a central data analysis platform. RESULTS: Application of the integrated system from August to December 2020 enabled a characterization of viral population structure, analysis of 4 outbreaks at a maximum care hospital, and genetically based identification of 5 putative population infection clusters, all of which were confirmed by contact tracing. The system contributed to the development of improved hospital infection control and prevention measures and enabled the identification of previously unrecognized transmission chains, involving a martial arts gym and establishing a link between the hospital to the local population. CONCLUSIONS: Integrated systems of genomic surveillance could contribute to the monitoring and, potentially, improved management of SARS-CoV-2 transmission in the population.

[Air and maritime transport during the COVID-19 pandemic in Germany: challenges for the public health service]. / Flug- und Schiffsverkehr während der COVID-19-Pandemie in Deutschland: Herausforderungen für den Öffentlichen Gesundheitsdienst.

COVID-19 has been challenging our society since January 2020. Due to global travel, the new coronavirus has rapidly spread worldwide. This article aims to provide an overview of the challenges in implementing measures in the air and maritime transport sector from the perspective of the German Public Health Service (Öffentlicher Gesundheitsdienst, ÖGD). Significant events and measures for air and maritime transport between January and August 2020 were selected. Lessons learned are discussed.During the COVID-19 pandemic, the ÖGD has been operating in a field of tension between the dynamics of scientific knowledge, political decision-making, social acceptance and consent.There are specific challenges at points of entry such as airports and seaports. These include staff shortages and the need to implement measures with a high organisational effort at very short notice such as health authority passenger checks carried out on aircraft, the establishment of test centres at points of entry and control of compliance with quarantine measures. Aggravating the situation, passenger lists, which are necessary for effective contact tracing, are often not available or incomplete. There is also a lack of digital tools for contact tracing but also, for example, the exchange of personal data within the ÖGD. Further difficulties in outbreak management arise from the cramped conditions on board ships and from the potential psychological stress on crew members and passengers, which have not yet been sufficiently considered.In view of all these challenges, it is paramount to strengthen the German Public Health Service in general and at points of entry and to intensify the exchange between the national, federal state and local levels.