Author : Gage Kahl Moreno
Publisher :
ISBN 13 :
Total Pages : 317 pages
Book Rating : 4.:/5 (125 download)
Book Synopsis Characterization of SARS-CoV-2 Introduction and Spread in Southern Wisconsin by : Gage Kahl Moreno
Download or read book Characterization of SARS-CoV-2 Introduction and Spread in Southern Wisconsin written by Gage Kahl Moreno and published by . This book was released on 2021 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) took the world by storm in early 2020, amassing over 153 million confirmed cases as of May 5, 2021. Whole-genome sequencing of confirmed SARS-CoV-2 cases has been used to infer patterns of viral transmission, identify putative introductions of the virus, and provide surveillance on established transmission chains. Aside from tracking the spread of SARS-CoV-2, sequencing data can provide insights into the efficacy of mitigation efforts and forecast the future trajectory of local outbreaks. In this dissertation I focus on exploring the factors that influenced SARS-CoV-2 introduction and spread in southern Wisconsin. Chapter 1 reviews the current state of the pandemic and takes a deeper look into what is known about SARS-CoV-2 replication, the factors that influence SARS-CoV-2 spread, and the preventative measure that can be implemented to slow the spread of SARS-CoV-2. In chapter 2, I describe our work characterizing the initial introduction and spread of SARS-CoV-2 in Dane and Milwaukee counties. These counties are the two most populous counties in southern Wisconsin, separated by only ~100km. Dane County had the 12th confirmed SARS-CoV-2 in the United States, but this did not lead to descendant cryptic spread, posited as the cause of many local outbreaks early in the pandemic. Instead, the Dane County outbreak was seeded by multiple later introductions, followed by limited community spread. In contrast, relatively few introductions in Milwaukee County led to extensive community spread. We characterized the efficacy of Wisconsin's "Safer at Home" order and found that viral spread decreased by at least 40% in both Dane and Milwaukee counties. This suggested that, at least early in the pandemic, patterns of SARS-CoV-2 transmission varied substantially even in nearby communities. In chapter 3, I describe our work tracing patterns of SARS-CoV-2 spread in the context of hospitals and clinics. Despite the use of personal protective equipment (PPE) and other strategies to decrease risk of infection, front-line healthcare workers (HCWs) are at increased risk for infection with SARS-CoV-2 compared to the general population. Using a computational contact tracing tool, informal interviews, and genomic sequencing of HCWs and patient contacts, we evaluate the efficacy of current PPE protocols and other preventative measures put in place at a major academic biomedical institution in the American Upper Midwest. We found that the majority of HCWs evaluated, had viral sequences that could be traced to the outside community, suggesting that PPE protocols and preventative measures in place were effective at suppressing viral spread within the institution evaluated here. In chapter 4, I describe our work characterizing an outbreak of SARS-CoV-2 in two residence halls on the University of Wisconsin-Madison's campus. Universities represent high-risk settings for COVID-19 outbreaks, as they combine congregate living situations with high levels of social activity, and a young population that is unlikely to experience severe disease. The University of Wisconsin - Madison had an outbreak of SARS-CoV-2 during Fall 2020 resulting in which 3,485 students tested positive during August - October 2020. This rapid uptick in cases led the university to quarantine two residence halls to contain further SARS-CoV-2 spread. We combine genomic sequencing from these two residence halls, and with 5% of community sequences from Dane County to reveal limited downstream transmission from the residence hall virus-es. Our results suggest that containment strategies including large-scale quarantines in congregate living situations (such as in dorms) and suspension of on-campus activities may be effective when experiencing large-scale outbreaks, when implemented rapidly and effectively. In chapter 5, I describe our epidemiological investigation into two intercollegiate outbreaks of SARS-CoV-2 despite having mandatory daily antigen testing. High frequen-cy, rapid turnaround SARS-CoV-2 testing continues to be proposed as a way of efficiently identifying and mitigating transmission in congregate settings. Despite implementation of daily antigen testing using Quidel's Sofia SARS Antigen Fluorescent Immunoassay (FIA), a university's athletics program experienced two SARS-CoV-2 outbreaks, one within a team, and one between another intercollegiate program. Sequencing revealed that each outbreak could be traced to a single cluster, indicating that there was transmission between individuals despite testing negative. These findings suggest that antigen testing alone, even when mandated and directly observed, may not be sufficient as an intervention to prevent SARS-CoV-2 outbreaks in congregate settings, and highlights the importance of supplementing serial antigen testing with appropriate mitigation strategies to prevent SARS-CoV-2 outbreak in congregate settings. Taken together, this work expands researchers' ability to understand the factors that influence SARS-CoV-2 spread, but also has informed the efficacy of a variety of different prevention measures taken during the pandemic. Our work characterizing transmission dynamics that occurred early in the pandemic enables researchers, and public health officials, to better understand how viral spread is initiated and differs between closely related communities. Additionally, our work investigating SARS-CoV-2 transmission in hospitals, and universities has highlighted strengths and weaknesses of SARS-CoV-2 prevention measures and enabled public health officials to strengthen their recommendations for slowing the spread of SARS-CoV-2. Altogether, this work lays the groundwork for using genomic surveillance to better understand transmission dynamics in specific outbreak settings, and in the general population.
