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

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Abstract

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.

Article activity feed

  1. SciScore for 10.1101/2021.02.13.21251678: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    SARS-CoV-2 dashboard application: The SARS-CoV-2 dashboard web application consists of a Python/Flask back-end and a browser front-end utilizing Bootstrap (https://getbootstrap.com/), JQuery (https://jquery.com/) and D3 [Bostock et al. 2011] for visualization.
    Python/Flask
    suggested: None
    Phylogenetic and minimum spanning tree analyses: Phylogenetic trees were computed with RAxML [Stamatakis 2014] based on multiple sequence alignments computed with Geneious 10.2.6 (https://www.geneious.com) and visualized with iTol [Letunic and Bork 2016].
    RAxML
    suggested: (RAxML, RRID:SCR_006086)
    Geneious
    suggested: (Geneious, RRID:SCR_010519)
    Minimum spanning trees of hospital outbreaks and related samples from the surveillance cohort and GISAID were computed with the Python library networkx version 2.5 and were visualized with Cytoscape version 3.8.2 and Inkscape version 0.92.
    Python
    suggested: (IPython, RRID:SCR_001658)
    Cytoscape
    suggested: (Cytoscape, RRID:SCR_003032)
    Inkscape
    suggested: (Inkscape, RRID:SCR_014479)
    Fast Nanopore sequencing experiment: The following modifications were applied to the Nanopore sequencing and analysis pipeline described above to improve total turn-around time from sample receipt to generation of the consensus sequence: (i) cDNA synthesis and PCR amplification were carried out as described in the Artic network SARS-CoV-2 protocol; however, library preparation was done by two trained personnel resulting in 10.5h from sample to MinION loading (Supplementary Figure 3); (ii) live high-accuracy Guppy base calling was set up on the MinION control workstation, utilizing a GeForce RTX 2080 Ti GPU; (iii) at defined times after the start of the sequencing run (15h, 17h, 19h, 21h, 23h, 25h, 27h, 37h, 48h, 63h, 72h), the Artic bioinformatics pipeline (see above; using only Medaka; runtime 0.5 - 1.5 hours on the MinION control workstation with 40 Intel Xeon Silver 4114 cores) was applied to the generated sequencing data, and genome completeness per sample (here defined as the number of non-N bases in the generated consensus sequences) was measured.
    MinION
    suggested: (MinION, RRID:SCR_017985)
    After the run had finished, final analysis was performed with the full Artic pipeline and curation of the resulting assemblies was based on both the variants called by Medaka and Nanopolish.
    Nanopolish
    suggested: (Nanopolish, RRID:SCR_016157)

    Results from OddPub: Thank you for sharing your code.


    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Limitations of this study include the utilized convenience sampling scheme, the relatively low proportion of sequenced positive cases over the sampling period, and the retrospective integration of genetic and contact tracing data. Addressing these in a follow-up study aiming for comprehensive case coverage, ultra-rapid turnaround times, real-time data sharing and integration with local public health authorities would be a natural extension of the work presented here and will demonstrate the full potential of integrated genomic surveillance with respect to the SARS-CoV-2 pandemic.

    Results from TrialIdentifier: No clinical trial numbers were referenced.


    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.


    Results from JetFighter: We did not find any issues relating to colormaps.


    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

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