COVID-19 is a major global health threat with over 440 million cases and 10.6 million deaths to date. Changes in social mixing patterns and shifting resources towards COVID-19 have had negative repercussions in the control of diseases such as tuberculosis (TB), the leading cause of infectious disease mortality in 2019, with 1.4 million deaths worldwide. The impact of efforts to curb the COVID-19 pandemic, and the impact of mitigation strategies on TB control require further study. The overarching goal of this dissertation was to evaluate local transmission dynamics of COVID-19 and the impact of mitigation strategies on both pandemic spread and drug-resistant TB control.
In the first study, we used a network-based model to study the relationship between contact tracing activities and hospital utilization. We found that no isolated or combined contact tracing intervention could prevent excess strain on ICU bed capacity in the state of Georgia. The positive effects of contact tracing were magnified within the period of time shortly after index case diagnosis, and plateaued after approximately 1 week.
In the second study, we utilized individual-level exposure histories collected through case investigation and contact tracing interviews to construct the contact tracing networks of COVID-19 at Emory University during the 2020-2021 school year. We found minimal clustering, a low proportion of asymptomatic cases, and higher secondary attack rates among contacts of symptomatic cases. Our results suggest it was unlikely that asymptomatic cases were missing from the observed network.
In the third study, we described changes in the number, spatial distribution, and neighborhood characteristics of drug-resistant TB cases before and after the COVID-19 national lockdowns in KwaZulu-Natal, South Africa. We observed a 29% reduction in drug-resistant TB cases diagnosed in the province after the lockdowns. Further, we observed that cases diagnosed after the lockdowns reported worse living conditions and fewer household resources.
The findings from this dissertation contribute to our understanding of the impact of contact tracing optimization on hospitalization and ICU utilization at a community level, important drivers of transmission in the setting of a university community, and the impact of COVID-19 mitigation strategies on drug-resistant TB control.
Table of Contents
Chapter 1: Introduction 1
1.1 Background and Significance – COVID-19 1
1.2 Background and Significance – Tuberculosis 18
1.3 Significance and Overview of Aims 26
1.4 Specific Aims 28
1.5 Data Sources 29
Chapter 2: The balance between public health capacity and clinical capacity in the early stages of the COVID-19 pandemic in the state of Georgia: a modeling study 33
Chapter 3: The application of social network analysis to examine COVID-19 contact tracing networks in a university setting 61
Chapter 4: The impact of COVID-19 national lockdowns on drug-resistant tuberculosis in KwaZulu-Natal, South Africa: a spatial analysis 87
Chapter 5: Public Health Implications and Future Directions 119
Appendix I. Data Sources 126
Appendix II. Chapter 2 Technical Appendix 130
Appendix III. Chapter 3 Technical Appendix 137
Appendix IV. Chapter 4 Technical Appendix 143
About this Dissertation
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