County-level Associations Between Geographic and Sociodemographic Characteristics and Risk of Confirmed COVID-19 Clustering in the United States From 5 March to 13 May 2020
| Variable . | Week 7 (5–11 March) . | Week 8 (12–18 March) . | Week 9 (19–25 March) . | Week 10 (26 March—1 April) . | Week 11 (2–8 April) . | Week 12 (9–15 April) . | Week 13 (16–22 April) . | Week 14 (23–29 April) . | Week 15 (30 April–6 May) . | Week 16 (7–13 May) . |
|---|---|---|---|---|---|---|---|---|---|---|
| Area | ||||||||||
| Metro | 5.31 (2.90–9.72) | 3.63 (2.79–4.71) | 3.40 (2.73–4.24) | 3.16 (2.51–3.98) | 3.05 (2.49–3.74) | 1.93 (1.58–2.36) | 1.04 (.86–1.27) | 1.75 (1.43–2.13) | 1.34 (1.10–1.63) | 1.77 (1.45–2.15) |
| Urban | 3.26 (1.76–6.03) | 1.95 (1.49–2.54) | 2.17 (1.74–2.70) | 2.10 (1.67–2.64) | 1.65 (1.35–2.01) | 1.57 (1.29–1.92) | .88 (.72–1.07) | 1.05 (.87–1.28) | 1.01 (.83–1.22) | 1.08 (.90–1.31) |
| Rural | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Distance to nearest core airports (quartile) | ||||||||||
| Q1 (shortest) | 14.4 (5.75–35.8) | 24.6 (15.6–38.8) | 4.63 (3.70–5.79) | 2.30 (1.86–2.84) | 4.67 (3.76–5.79) | 2.75 (2.24–3.39) | 1.03 (.84–1.26) | 1.28 (1.04–1.56) | 1.57 (1.28–1.91) | 1.95 (1.59–2.38) |
| Q2 | 16.0 (6.43–39.8) | 20.0 (12.7–31.7) | 3.10 (2.48–3.88) | 1.39 (1.12–1.73) | 3.33 (2.69–4.13) | 1.98 (1.61–2.44) | 1.20 (.98–1.47) | 1.18 (.96–1.44) | 1.41 (1.15–1.72) | 1.93 (1.58–2.36) |
| Q3 | 12.0 (4.79–30.2) | 10.0 (6.30–16.0 | 2.16 (1.72–2.72) | 1.28 (1.02–1.59) | 2.83 (2.28–3.50) | 1.63 (1.32–2.00) | 1.10 (.89–1.34) | 1.21 (.99–1.48) | 1.36 (1.12–1.66) | 1.51 (1.23–1.84) |
| Q4 (longest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Population densitya (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.27 (1.78–6.02) | 3.20 (2.29–4.47) | 4.23 (3.32–5.39) | 1.93 (1.53–1.42) | 2.38 (1.92–2.95) | 1.93 (1.58–2.37) | 1.06 (.87–1.30) | 1.28 (1.04–1.57) | 1.34 (1.10–1.64) | 1.35 (1.10–1.65) |
| Q3 | 4.31 (2.38–7.80) | 7.41 (5.39–10.2) | 4.74 (3.72–6.03) | 2.30 (1.83–2.89) | 3.59 (2.90–4.45) | 1.58 (1.28–1.94) | 1.15 (.94–1.41) | 1.39 (1.13–1.70) | 1.54 (1.26–1.88) | 1.62 (1.32–1.98) |
| Q4 (highest) | 6.69 (3.77–11.9) | 9.56 (6.97–13.1) | 6.05 (4.75–7.70) | 3.15 (2.51–3.94) | 5.42 (4.36–6.75) | 1.83 (1.49–2.24) | 1.22 (1.00–1.49) | 2.25 (1.84–2.76) | 1.47 (1.20–1.79) | 2.56 (2.09–3.15) |
| % Minority populationb (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.11 (1.64–5.87) | 1.73 (1.35–2.22) | 1.35 (1.08–1.70) | 1.76 (1.38–2.23) | 1.22 (.99–1.50) | 1.28 (1.04–1.57) | .96 (.79–1.18) | .85 (.70–1.04) | 1.03 (.84–1.25) | .99 (.81–1.21) |
| Q3 | 5.45 (2.98–9.96) | 2.35 (1.84–2.99) | 2.40 (1.93–2.98) | 3.11 (2.47–3.92) | 2.29 (1.86–2.81) | 1.39 (1.13–1.71) | 1.09 (.89–1.34) | 1.23 (1.01–1.50) | 1.23 (1.01–1.50) | 1.43 (1.17–1.75) |
| Q4 (highest) | 6.93 (3.83–12.6) | 2.03 (1.59–2.60) | 4.77 (3.83–5.94) | 4.02 (3.20–5.06) | 3.98 (3.22–4.91) | 2.39 (1.95–2.93) | 1.01 (.82–1.23) | 1.01 (.83–1.24) | 1.56 (1.28–1.91) | 2.34 (1.91–2.87) |
| % Older populationc (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.27 (.87–1.86) | .91 (.73–1.13) | 1.04 (.85–1.27) | 1.07 (.88–1.32) | .79 (.65–.96) | .74 (.60–.90) | 1.08 (.88–1.32) | 1.04 (.85–1.27) | .97 (.80–1.19) | .88 (.72–1.07) |
| Q3 | .92 (.61–1.38) | .91 (.73–1.13) | .91 (.75–1.12) | .74 (.60–.91) | .76 (.63–.93) | .90 (.74–1.10) | .93 (.76–1.14) | 1.18 (.97–1.44) | .95 (.78–1.16) | .76 (.62–.93) |
| Q4 (highest) | .66 (.42–1.02) | .57 (.45–.72) | .63 (.51–.77) | .52 (.42–.65) | .46 (.37–.56) | .63 (.52–.77) | .99 (.81–1.21) | 1.19 (.97–1.45) | .85 (.70–1.04) | .68 (.56–.83) |
| % Poverty d (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.70 (1.12–2.56) | 1.12 (.90–1.41) | 1.28 (1.04–1.57) | 1.04 (.84–1.30) | 1.00 (.82–1.22) | 1.26 (1.03–1.55) | .89 (.72–1.09) | 1.08 (.88–1.32) | 1.06 (.87–1.30) | .84 (.69–1.02) |
| Q3 | .81 (.50–1.31) | 1.09 (.87–1.36) | 1.26 (1.03–1.55) | 1.43 (1.15–1.77) | 1.33 (1.09–1.63) | 1.07 (.87–1.31) | .94 (.76–1.15) | .82 (.67–1.01) | .96 (.79–1.17) | .77 (.63–.94) |
| Q4 (highest) | 1.73 (1.15–2.61) | .68 (.54–0.87) | 1.32 (1.07–1.62) | 1.66 (1.35–2.05) | 1.49 (1.22–1.82) | 1.32 (1.08–1.62) | 1.05 (.86–1.29) | .59 (.48–.73) | 1.33 (1.09–1.63) | .89 (.73–1.09) |
| Variable . | Week 7 (5–11 March) . | Week 8 (12–18 March) . | Week 9 (19–25 March) . | Week 10 (26 March—1 April) . | Week 11 (2–8 April) . | Week 12 (9–15 April) . | Week 13 (16–22 April) . | Week 14 (23–29 April) . | Week 15 (30 April–6 May) . | Week 16 (7–13 May) . |
|---|---|---|---|---|---|---|---|---|---|---|
| Area | ||||||||||
| Metro | 5.31 (2.90–9.72) | 3.63 (2.79–4.71) | 3.40 (2.73–4.24) | 3.16 (2.51–3.98) | 3.05 (2.49–3.74) | 1.93 (1.58–2.36) | 1.04 (.86–1.27) | 1.75 (1.43–2.13) | 1.34 (1.10–1.63) | 1.77 (1.45–2.15) |
| Urban | 3.26 (1.76–6.03) | 1.95 (1.49–2.54) | 2.17 (1.74–2.70) | 2.10 (1.67–2.64) | 1.65 (1.35–2.01) | 1.57 (1.29–1.92) | .88 (.72–1.07) | 1.05 (.87–1.28) | 1.01 (.83–1.22) | 1.08 (.90–1.31) |
| Rural | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Distance to nearest core airports (quartile) | ||||||||||
| Q1 (shortest) | 14.4 (5.75–35.8) | 24.6 (15.6–38.8) | 4.63 (3.70–5.79) | 2.30 (1.86–2.84) | 4.67 (3.76–5.79) | 2.75 (2.24–3.39) | 1.03 (.84–1.26) | 1.28 (1.04–1.56) | 1.57 (1.28–1.91) | 1.95 (1.59–2.38) |
| Q2 | 16.0 (6.43–39.8) | 20.0 (12.7–31.7) | 3.10 (2.48–3.88) | 1.39 (1.12–1.73) | 3.33 (2.69–4.13) | 1.98 (1.61–2.44) | 1.20 (.98–1.47) | 1.18 (.96–1.44) | 1.41 (1.15–1.72) | 1.93 (1.58–2.36) |
| Q3 | 12.0 (4.79–30.2) | 10.0 (6.30–16.0 | 2.16 (1.72–2.72) | 1.28 (1.02–1.59) | 2.83 (2.28–3.50) | 1.63 (1.32–2.00) | 1.10 (.89–1.34) | 1.21 (.99–1.48) | 1.36 (1.12–1.66) | 1.51 (1.23–1.84) |
| Q4 (longest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Population densitya (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.27 (1.78–6.02) | 3.20 (2.29–4.47) | 4.23 (3.32–5.39) | 1.93 (1.53–1.42) | 2.38 (1.92–2.95) | 1.93 (1.58–2.37) | 1.06 (.87–1.30) | 1.28 (1.04–1.57) | 1.34 (1.10–1.64) | 1.35 (1.10–1.65) |
| Q3 | 4.31 (2.38–7.80) | 7.41 (5.39–10.2) | 4.74 (3.72–6.03) | 2.30 (1.83–2.89) | 3.59 (2.90–4.45) | 1.58 (1.28–1.94) | 1.15 (.94–1.41) | 1.39 (1.13–1.70) | 1.54 (1.26–1.88) | 1.62 (1.32–1.98) |
| Q4 (highest) | 6.69 (3.77–11.9) | 9.56 (6.97–13.1) | 6.05 (4.75–7.70) | 3.15 (2.51–3.94) | 5.42 (4.36–6.75) | 1.83 (1.49–2.24) | 1.22 (1.00–1.49) | 2.25 (1.84–2.76) | 1.47 (1.20–1.79) | 2.56 (2.09–3.15) |
| % Minority populationb (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.11 (1.64–5.87) | 1.73 (1.35–2.22) | 1.35 (1.08–1.70) | 1.76 (1.38–2.23) | 1.22 (.99–1.50) | 1.28 (1.04–1.57) | .96 (.79–1.18) | .85 (.70–1.04) | 1.03 (.84–1.25) | .99 (.81–1.21) |
| Q3 | 5.45 (2.98–9.96) | 2.35 (1.84–2.99) | 2.40 (1.93–2.98) | 3.11 (2.47–3.92) | 2.29 (1.86–2.81) | 1.39 (1.13–1.71) | 1.09 (.89–1.34) | 1.23 (1.01–1.50) | 1.23 (1.01–1.50) | 1.43 (1.17–1.75) |
| Q4 (highest) | 6.93 (3.83–12.6) | 2.03 (1.59–2.60) | 4.77 (3.83–5.94) | 4.02 (3.20–5.06) | 3.98 (3.22–4.91) | 2.39 (1.95–2.93) | 1.01 (.82–1.23) | 1.01 (.83–1.24) | 1.56 (1.28–1.91) | 2.34 (1.91–2.87) |
| % Older populationc (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.27 (.87–1.86) | .91 (.73–1.13) | 1.04 (.85–1.27) | 1.07 (.88–1.32) | .79 (.65–.96) | .74 (.60–.90) | 1.08 (.88–1.32) | 1.04 (.85–1.27) | .97 (.80–1.19) | .88 (.72–1.07) |
| Q3 | .92 (.61–1.38) | .91 (.73–1.13) | .91 (.75–1.12) | .74 (.60–.91) | .76 (.63–.93) | .90 (.74–1.10) | .93 (.76–1.14) | 1.18 (.97–1.44) | .95 (.78–1.16) | .76 (.62–.93) |
| Q4 (highest) | .66 (.42–1.02) | .57 (.45–.72) | .63 (.51–.77) | .52 (.42–.65) | .46 (.37–.56) | .63 (.52–.77) | .99 (.81–1.21) | 1.19 (.97–1.45) | .85 (.70–1.04) | .68 (.56–.83) |
| % Poverty d (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.70 (1.12–2.56) | 1.12 (.90–1.41) | 1.28 (1.04–1.57) | 1.04 (.84–1.30) | 1.00 (.82–1.22) | 1.26 (1.03–1.55) | .89 (.72–1.09) | 1.08 (.88–1.32) | 1.06 (.87–1.30) | .84 (.69–1.02) |
| Q3 | .81 (.50–1.31) | 1.09 (.87–1.36) | 1.26 (1.03–1.55) | 1.43 (1.15–1.77) | 1.33 (1.09–1.63) | 1.07 (.87–1.31) | .94 (.76–1.15) | .82 (.67–1.01) | .96 (.79–1.17) | .77 (.63–.94) |
| Q4 (highest) | 1.73 (1.15–2.61) | .68 (.54–0.87) | 1.32 (1.07–1.62) | 1.66 (1.35–2.05) | 1.49 (1.22–1.82) | 1.32 (1.08–1.62) | 1.05 (.86–1.29) | .59 (.48–.73) | 1.33 (1.09–1.63) | .89 (.73–1.09) |
Data are presented as odds ratios (95% confidence interval). The regression analysis was performed for counties in 48 contiguous states and Washington, DC.
Abbreviations: COVID-19, coronavirus disease 2019; Q, quartile.
aThe number of persons per square mile of lands.
bPercentage of racial and ethnic minorities.
cPercentage of persons aged 65 years or older.
dPercentage of persons below the federal poverty line.
County-level Associations Between Geographic and Sociodemographic Characteristics and Risk of Confirmed COVID-19 Clustering in the United States From 5 March to 13 May 2020
| Variable . | Week 7 (5–11 March) . | Week 8 (12–18 March) . | Week 9 (19–25 March) . | Week 10 (26 March—1 April) . | Week 11 (2–8 April) . | Week 12 (9–15 April) . | Week 13 (16–22 April) . | Week 14 (23–29 April) . | Week 15 (30 April–6 May) . | Week 16 (7–13 May) . |
|---|---|---|---|---|---|---|---|---|---|---|
| Area | ||||||||||
| Metro | 5.31 (2.90–9.72) | 3.63 (2.79–4.71) | 3.40 (2.73–4.24) | 3.16 (2.51–3.98) | 3.05 (2.49–3.74) | 1.93 (1.58–2.36) | 1.04 (.86–1.27) | 1.75 (1.43–2.13) | 1.34 (1.10–1.63) | 1.77 (1.45–2.15) |
| Urban | 3.26 (1.76–6.03) | 1.95 (1.49–2.54) | 2.17 (1.74–2.70) | 2.10 (1.67–2.64) | 1.65 (1.35–2.01) | 1.57 (1.29–1.92) | .88 (.72–1.07) | 1.05 (.87–1.28) | 1.01 (.83–1.22) | 1.08 (.90–1.31) |
| Rural | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Distance to nearest core airports (quartile) | ||||||||||
| Q1 (shortest) | 14.4 (5.75–35.8) | 24.6 (15.6–38.8) | 4.63 (3.70–5.79) | 2.30 (1.86–2.84) | 4.67 (3.76–5.79) | 2.75 (2.24–3.39) | 1.03 (.84–1.26) | 1.28 (1.04–1.56) | 1.57 (1.28–1.91) | 1.95 (1.59–2.38) |
| Q2 | 16.0 (6.43–39.8) | 20.0 (12.7–31.7) | 3.10 (2.48–3.88) | 1.39 (1.12–1.73) | 3.33 (2.69–4.13) | 1.98 (1.61–2.44) | 1.20 (.98–1.47) | 1.18 (.96–1.44) | 1.41 (1.15–1.72) | 1.93 (1.58–2.36) |
| Q3 | 12.0 (4.79–30.2) | 10.0 (6.30–16.0 | 2.16 (1.72–2.72) | 1.28 (1.02–1.59) | 2.83 (2.28–3.50) | 1.63 (1.32–2.00) | 1.10 (.89–1.34) | 1.21 (.99–1.48) | 1.36 (1.12–1.66) | 1.51 (1.23–1.84) |
| Q4 (longest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Population densitya (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.27 (1.78–6.02) | 3.20 (2.29–4.47) | 4.23 (3.32–5.39) | 1.93 (1.53–1.42) | 2.38 (1.92–2.95) | 1.93 (1.58–2.37) | 1.06 (.87–1.30) | 1.28 (1.04–1.57) | 1.34 (1.10–1.64) | 1.35 (1.10–1.65) |
| Q3 | 4.31 (2.38–7.80) | 7.41 (5.39–10.2) | 4.74 (3.72–6.03) | 2.30 (1.83–2.89) | 3.59 (2.90–4.45) | 1.58 (1.28–1.94) | 1.15 (.94–1.41) | 1.39 (1.13–1.70) | 1.54 (1.26–1.88) | 1.62 (1.32–1.98) |
| Q4 (highest) | 6.69 (3.77–11.9) | 9.56 (6.97–13.1) | 6.05 (4.75–7.70) | 3.15 (2.51–3.94) | 5.42 (4.36–6.75) | 1.83 (1.49–2.24) | 1.22 (1.00–1.49) | 2.25 (1.84–2.76) | 1.47 (1.20–1.79) | 2.56 (2.09–3.15) |
| % Minority populationb (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.11 (1.64–5.87) | 1.73 (1.35–2.22) | 1.35 (1.08–1.70) | 1.76 (1.38–2.23) | 1.22 (.99–1.50) | 1.28 (1.04–1.57) | .96 (.79–1.18) | .85 (.70–1.04) | 1.03 (.84–1.25) | .99 (.81–1.21) |
| Q3 | 5.45 (2.98–9.96) | 2.35 (1.84–2.99) | 2.40 (1.93–2.98) | 3.11 (2.47–3.92) | 2.29 (1.86–2.81) | 1.39 (1.13–1.71) | 1.09 (.89–1.34) | 1.23 (1.01–1.50) | 1.23 (1.01–1.50) | 1.43 (1.17–1.75) |
| Q4 (highest) | 6.93 (3.83–12.6) | 2.03 (1.59–2.60) | 4.77 (3.83–5.94) | 4.02 (3.20–5.06) | 3.98 (3.22–4.91) | 2.39 (1.95–2.93) | 1.01 (.82–1.23) | 1.01 (.83–1.24) | 1.56 (1.28–1.91) | 2.34 (1.91–2.87) |
| % Older populationc (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.27 (.87–1.86) | .91 (.73–1.13) | 1.04 (.85–1.27) | 1.07 (.88–1.32) | .79 (.65–.96) | .74 (.60–.90) | 1.08 (.88–1.32) | 1.04 (.85–1.27) | .97 (.80–1.19) | .88 (.72–1.07) |
| Q3 | .92 (.61–1.38) | .91 (.73–1.13) | .91 (.75–1.12) | .74 (.60–.91) | .76 (.63–.93) | .90 (.74–1.10) | .93 (.76–1.14) | 1.18 (.97–1.44) | .95 (.78–1.16) | .76 (.62–.93) |
| Q4 (highest) | .66 (.42–1.02) | .57 (.45–.72) | .63 (.51–.77) | .52 (.42–.65) | .46 (.37–.56) | .63 (.52–.77) | .99 (.81–1.21) | 1.19 (.97–1.45) | .85 (.70–1.04) | .68 (.56–.83) |
| % Poverty d (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.70 (1.12–2.56) | 1.12 (.90–1.41) | 1.28 (1.04–1.57) | 1.04 (.84–1.30) | 1.00 (.82–1.22) | 1.26 (1.03–1.55) | .89 (.72–1.09) | 1.08 (.88–1.32) | 1.06 (.87–1.30) | .84 (.69–1.02) |
| Q3 | .81 (.50–1.31) | 1.09 (.87–1.36) | 1.26 (1.03–1.55) | 1.43 (1.15–1.77) | 1.33 (1.09–1.63) | 1.07 (.87–1.31) | .94 (.76–1.15) | .82 (.67–1.01) | .96 (.79–1.17) | .77 (.63–.94) |
| Q4 (highest) | 1.73 (1.15–2.61) | .68 (.54–0.87) | 1.32 (1.07–1.62) | 1.66 (1.35–2.05) | 1.49 (1.22–1.82) | 1.32 (1.08–1.62) | 1.05 (.86–1.29) | .59 (.48–.73) | 1.33 (1.09–1.63) | .89 (.73–1.09) |
| Variable . | Week 7 (5–11 March) . | Week 8 (12–18 March) . | Week 9 (19–25 March) . | Week 10 (26 March—1 April) . | Week 11 (2–8 April) . | Week 12 (9–15 April) . | Week 13 (16–22 April) . | Week 14 (23–29 April) . | Week 15 (30 April–6 May) . | Week 16 (7–13 May) . |
|---|---|---|---|---|---|---|---|---|---|---|
| Area | ||||||||||
| Metro | 5.31 (2.90–9.72) | 3.63 (2.79–4.71) | 3.40 (2.73–4.24) | 3.16 (2.51–3.98) | 3.05 (2.49–3.74) | 1.93 (1.58–2.36) | 1.04 (.86–1.27) | 1.75 (1.43–2.13) | 1.34 (1.10–1.63) | 1.77 (1.45–2.15) |
| Urban | 3.26 (1.76–6.03) | 1.95 (1.49–2.54) | 2.17 (1.74–2.70) | 2.10 (1.67–2.64) | 1.65 (1.35–2.01) | 1.57 (1.29–1.92) | .88 (.72–1.07) | 1.05 (.87–1.28) | 1.01 (.83–1.22) | 1.08 (.90–1.31) |
| Rural | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Distance to nearest core airports (quartile) | ||||||||||
| Q1 (shortest) | 14.4 (5.75–35.8) | 24.6 (15.6–38.8) | 4.63 (3.70–5.79) | 2.30 (1.86–2.84) | 4.67 (3.76–5.79) | 2.75 (2.24–3.39) | 1.03 (.84–1.26) | 1.28 (1.04–1.56) | 1.57 (1.28–1.91) | 1.95 (1.59–2.38) |
| Q2 | 16.0 (6.43–39.8) | 20.0 (12.7–31.7) | 3.10 (2.48–3.88) | 1.39 (1.12–1.73) | 3.33 (2.69–4.13) | 1.98 (1.61–2.44) | 1.20 (.98–1.47) | 1.18 (.96–1.44) | 1.41 (1.15–1.72) | 1.93 (1.58–2.36) |
| Q3 | 12.0 (4.79–30.2) | 10.0 (6.30–16.0 | 2.16 (1.72–2.72) | 1.28 (1.02–1.59) | 2.83 (2.28–3.50) | 1.63 (1.32–2.00) | 1.10 (.89–1.34) | 1.21 (.99–1.48) | 1.36 (1.12–1.66) | 1.51 (1.23–1.84) |
| Q4 (longest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Population densitya (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.27 (1.78–6.02) | 3.20 (2.29–4.47) | 4.23 (3.32–5.39) | 1.93 (1.53–1.42) | 2.38 (1.92–2.95) | 1.93 (1.58–2.37) | 1.06 (.87–1.30) | 1.28 (1.04–1.57) | 1.34 (1.10–1.64) | 1.35 (1.10–1.65) |
| Q3 | 4.31 (2.38–7.80) | 7.41 (5.39–10.2) | 4.74 (3.72–6.03) | 2.30 (1.83–2.89) | 3.59 (2.90–4.45) | 1.58 (1.28–1.94) | 1.15 (.94–1.41) | 1.39 (1.13–1.70) | 1.54 (1.26–1.88) | 1.62 (1.32–1.98) |
| Q4 (highest) | 6.69 (3.77–11.9) | 9.56 (6.97–13.1) | 6.05 (4.75–7.70) | 3.15 (2.51–3.94) | 5.42 (4.36–6.75) | 1.83 (1.49–2.24) | 1.22 (1.00–1.49) | 2.25 (1.84–2.76) | 1.47 (1.20–1.79) | 2.56 (2.09–3.15) |
| % Minority populationb (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 3.11 (1.64–5.87) | 1.73 (1.35–2.22) | 1.35 (1.08–1.70) | 1.76 (1.38–2.23) | 1.22 (.99–1.50) | 1.28 (1.04–1.57) | .96 (.79–1.18) | .85 (.70–1.04) | 1.03 (.84–1.25) | .99 (.81–1.21) |
| Q3 | 5.45 (2.98–9.96) | 2.35 (1.84–2.99) | 2.40 (1.93–2.98) | 3.11 (2.47–3.92) | 2.29 (1.86–2.81) | 1.39 (1.13–1.71) | 1.09 (.89–1.34) | 1.23 (1.01–1.50) | 1.23 (1.01–1.50) | 1.43 (1.17–1.75) |
| Q4 (highest) | 6.93 (3.83–12.6) | 2.03 (1.59–2.60) | 4.77 (3.83–5.94) | 4.02 (3.20–5.06) | 3.98 (3.22–4.91) | 2.39 (1.95–2.93) | 1.01 (.82–1.23) | 1.01 (.83–1.24) | 1.56 (1.28–1.91) | 2.34 (1.91–2.87) |
| % Older populationc (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.27 (.87–1.86) | .91 (.73–1.13) | 1.04 (.85–1.27) | 1.07 (.88–1.32) | .79 (.65–.96) | .74 (.60–.90) | 1.08 (.88–1.32) | 1.04 (.85–1.27) | .97 (.80–1.19) | .88 (.72–1.07) |
| Q3 | .92 (.61–1.38) | .91 (.73–1.13) | .91 (.75–1.12) | .74 (.60–.91) | .76 (.63–.93) | .90 (.74–1.10) | .93 (.76–1.14) | 1.18 (.97–1.44) | .95 (.78–1.16) | .76 (.62–.93) |
| Q4 (highest) | .66 (.42–1.02) | .57 (.45–.72) | .63 (.51–.77) | .52 (.42–.65) | .46 (.37–.56) | .63 (.52–.77) | .99 (.81–1.21) | 1.19 (.97–1.45) | .85 (.70–1.04) | .68 (.56–.83) |
| % Poverty d (quartile) | ||||||||||
| Q1 (lowest) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Q2 | 1.70 (1.12–2.56) | 1.12 (.90–1.41) | 1.28 (1.04–1.57) | 1.04 (.84–1.30) | 1.00 (.82–1.22) | 1.26 (1.03–1.55) | .89 (.72–1.09) | 1.08 (.88–1.32) | 1.06 (.87–1.30) | .84 (.69–1.02) |
| Q3 | .81 (.50–1.31) | 1.09 (.87–1.36) | 1.26 (1.03–1.55) | 1.43 (1.15–1.77) | 1.33 (1.09–1.63) | 1.07 (.87–1.31) | .94 (.76–1.15) | .82 (.67–1.01) | .96 (.79–1.17) | .77 (.63–.94) |
| Q4 (highest) | 1.73 (1.15–2.61) | .68 (.54–0.87) | 1.32 (1.07–1.62) | 1.66 (1.35–2.05) | 1.49 (1.22–1.82) | 1.32 (1.08–1.62) | 1.05 (.86–1.29) | .59 (.48–.73) | 1.33 (1.09–1.63) | .89 (.73–1.09) |
Data are presented as odds ratios (95% confidence interval). The regression analysis was performed for counties in 48 contiguous states and Washington, DC.
Abbreviations: COVID-19, coronavirus disease 2019; Q, quartile.
aThe number of persons per square mile of lands.
bPercentage of racial and ethnic minorities.
cPercentage of persons aged 65 years or older.
dPercentage of persons below the federal poverty line.
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