An Ecological Analysis of Overcrowded Housing, Vaccination coverage, and COVID-19 Case and Death Rates Open Access

Ampofo, Yadah (Spring 2022)

Permanent URL: https://etd.library.emory.edu/concern/etds/5q47rp989?locale=en
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Abstract

Social distancing and COVID-19 vaccinations are core public health mitigation measures to curb the spread of the SARS-CoV-2 virus in the United States. Overcrowded housing limits the ability to socially distance, and low community vaccination coverage leads to population susceptibility to the virus. We sought to investigate the association of overcrowded housing and vaccination coverage with new monthly COVID-19 case and death rates in 2021.

The unit of analysis was the county. The primary exposures include the proportion of households that were overcrowded (defined >1 person per room) and the cumulative population percentage that was vaccinated at the end of each month. Study outcomes were monthly new COVID-19 case and death rates per 100,000 population. We characterized monthly variations in the study exposures and outcomes and estimated their correlation by month in the 2021 year using Pearson coefficients. County vulnerability was categorized into four groups as: “High” (Top 25% overcrowded housing and Bottom 25% vaccination coverage); “High Overcrowded Housing” (Top 25% overcrowded housing and Top 75% vaccination coverage); “Low vaccination coverage” (Bottom 75% overcrowded housing and Bottom 25% vaccination coverage); and “Low” (Bottom 75% overcrowded housing and top 75% vaccination coverage). Associations of the composite vulnerability measure rates with COVID-19 case and death rates were estimated using linear regression. All statistical analyses accounted for calendar month through stratification or adjustment. 

Data from 2,137 U.S. counties were analyzed. The correlation of overcrowded housing and vaccination rates with COVID-19 outcomes remained weak throughout the year (range of r= -0.259 to r=0.2030). The proportion of counties categorized as having high vulnerability reduced from 24.9% in January to 0.084% in December. In the adjusted model accounting for county-level socio-demographic factors and calendar month, there were no statistically significant associations between high vulnerability and COVID-19 case rates (β = 2.18; 95% CI -32.8, 37.1 p = 0.963) or death rates (β = 0.80, 95% CI -0.3,1.9, p = 0.162).    

Despite weak monthly correlations among overcrowded housing, vaccination coverage, and COVID-19 outcomes at a county-level, we found no association of combined high overcrowded housing and low vaccination coverage with COVID-19 case or death rates during the 2021 year.

Table of Contents

Chapter 1: Introduction...........................................................................................................1

1.0 Background.............................................................................1

Chapter 2: Literature Review...................................................................................................5

2.0 COVID-19 Origins and Epidemiology .......................................................................................5

2.1 COVID-19 Transmission ...........................................................................................................5

2.2 COVID-19 Detection..................................................................................................................6

2.3 COVID-19 Mitigation and Prevention Measures ......................................................................7

2.4 Demographic Differences in COVID-19 Health Outcomes........................................................9 

2.5 The Socioeconomic Impact of the Disease................................................................................10

2.6 Overcrowded Housing .............................................................................................................10

2.7 The History of Crowded Housing and Health in the United States .........................................11

2.8 Overcrowded Housing: A potentially critical dimension of virus transmission ......................11

Knowledge gaps.............................................................................................................................13

Objectives ......................................................................................................................................13 

Chapter 3: Methods...............................................................................................................14

3.0 Study Design ............................................................................................................................14

3.1 Data Sources ............................................................................................................................14

3.2 Calculation of the Overcrowded Housing Proportion and Percent Variable ..........................15

3.3 Vaccination Variables..............................................................................................................16

3.4 New Monthly COVID-19 Case and Death Rate Variables ......................................................17

3.5 Composite Housing and Vaccination Vulnerability.................................................................17

3.6 County-Level Covariates .........................................................................................................18

3.7 Statistical Methods/Analysis ....................................................................................................19

3.8 Human Error & Bias ...............................................................................................................20 

Chapter 4: Results .................................................................................................................22

4.0 Descriptive Characteristics......................................................................................................22

4.1 Temporal Analysis of U.S. County-Level Vulnerability ..........................................................24

4.2 Linear and Multiple Regressions.............................................................................................25

4.3 Sensitivity Analyses of the Vaccination Coverage Threshold Changes ...................................26

Results: Tables & Figures .............................................................................................................28

Figure 1: Average New COVID-19 Cases per 100,000 Population...................................................................28

Figure 2: Average New COVID-19 Deaths per 100,000 Population ................................................................. 29 

Figure 3: Average New COVID-19 Vaccinations per 100,000 Population ....................................................... 30

Figure 4: Percentage of U.S. Counties within each Vulnerability Risk Category from January - December 2021 ......................... 31

Figure 5: U.S. County-Level Heat Map of Percent Overcrowded Housing ....................................................... 32

Figure 6: January 2021 U.S. County-Level Heat Map of the County-level Vulnerability Risk Category ......... ....................33

Figure 7: December 2021 U.S. County-Level Heat of the County-level Vulnerability Risk Category ................................. 34

Table 1: Summary of County Case, Death and Vaccination Rates Per 100,000 Population by Month ................................. 35

Table 2: Monthly Pearson Correlations between New COVID-19 Case, Death and Vaccination rates per 100,000 and Overcrowded Housing proportion ............................... 36

Table 3: The Total Number Counties in the Top 25% of the County-Level Overcrowded Housing ..................................... 37

Table 4: County-Level Associations of Vulnerability Measures and Demographic Characteristics with COVID-19 Cases per 100,000 Population ................................... 38

Table 5: County-Level Associations of Vulnerability Measures and Demographic Characteristics with COVID-19 Deaths per 100,000 Population ............................... 39 

Chapter 5: Discussion ...........................................................................................................40

Chapter 6: Conclusion...........................................................................................................47

Bibliography..........................................................................................................................49

Appendix A: Tables ...............................................................................................................57

Table 6: New Case rates per 100,000 regression results from fully adjusted multivariable models comparing counties with <25% versus <50% versus <75% high risk thresholds for Vaccine Coverage......................... 57

Table 7: New Death rates per 100,000 regression results from fully adjusted multivariable models comparing counties with <25% versus <50% versus <75% high risk thresholds for Vaccine Coverage. ............................. 58

Appendix B: Figures......................................................................................................................59

Figure 8: 2021 Monthly Variations in the Percentage of U.S. Counties within each Vulnerability Category at the 25% Vaccination Coverage Threshold....................... 59

Figure 9: 2021 Monthly Variations in the Percentage of U.S. Counties within each Vulnerability Category at the 50% Vaccination Threshold ....................................... 60

Figure 10: 2021 Monthly Variations in the Percentage of U.S. Counties within each Vulnerability Category at the 75% Vaccination Threshold ................................... 61 

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