Table 2. SARS-CoV-2 seropositivity by participant demographics and SARS-CoV-2 exposures and risk behaviors.
| Chadiza | Chipata | Chongwe | Lusaka | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SARS-CoV-2 Seropositive | Adjusted Odds Ratio | SARS-CoV-2 Seropositive | Adjusted Odds Ratio | SARS-CoV-2 Seropositive | Adjusted Odds Ratio | SARS-CoV-2 Seropositive | Adjusted Odds Ratio | |||||||||
| n | (%) | aOR | 95% CI | n | (%) | aOR | 95% CI | n | (%) | aOR | 95% CI | n | (%) | aOR | 95% CI | |
| Total | 707 | (43.8) | 1433 | (68.3) | 1565 | (64.1) | 1591 | (74.1) | ||||||||
| Age | ||||||||||||||||
| 15–19 | 182 | (41.6) | 1 | (ref) | 244 | (66.1) | 1 | (ref) | 330 | (63.7) | 1 | (ref) | 154 | (73.3) | 1 | (ref) |
| 20–29 | 343 | (45.1) | 1.23 | (0.96–1.58) | 808 | (67.9) | 1.12 | (0.86–1.46) | 823 | (63.3) | 1.00 | (0.80–1.25) | 947 | (73.0) | 0.98 | (0.69–1.40) |
| 30–39 | 114 | (45.4) | 1.12 | (0.80–1.56) | 338 | (70.3) | 1.31 | (0.96–1.79) | 352 | (66.3) | 1.21 | (0.92–1.59) | 443 | (76.9) | 1.22 | (0.83–1.80) |
| 40–49 | 12 | (46.2) | 1.43 | (0.61–3.33) | 36 | (83.7) | 2.76 | (1.16–6.58)* | 60 | (66.7) | 1.17 | (0.70–1.95) | 42 | (73.7) | 0.98 | (0.48–2.00) |
| Education | ||||||||||||||||
| No education | 156 | (41.4) | 0.91 | (0.70–1.18) | 108 | (63.2) | 0.86 | (0.59–1.26) | 44 | (57.1) | 1.17 | (0.70–1.95) | 16 | (51.6) | 0.44 | (0.19–1.00) |
| Some primary | 337 | (43.3) | 1 | (ref) | 329 | (63.5) | 1 | (ref) | 485 | (60.0) | 1 | (ref) | 296 | (71.7) | 1 | (ref) |
| Completed primary | 49 | (36.8) | 0.96 | (0.64–1.43) | 390 | (70.5) | 1.08 | (0.82–1.41) | 405 | (66.6) | 1.12 | (0.89–1.42) | 255 | (75.7) | 0.91 | (0.64–1.30) |
| Some secondary | 95 | (47.5) | 1.23 | (0.88–1.70) | 440 | (71.9) | 1.25 | (0.96–1.63) | 485 | (66.3) | 1.34 | (1.07–1.67) | 602 | (74.8) | 0.94 | (0.70–1.25) |
| Completed secondary or higher | 68 | (55.3) | 1.76 | (1.17–2.64)* | 161 | (67.1) | 1.14 | (0.81–1.61) | 146 | (67.9) | 1.64 | (1.16–2.31)* | 420 | (75.1) | 0.96 | (0.71–1.31) |
| Occupation | ||||||||||||||||
| Farmer | 596 | (43.1) | 0.63 | (0.37–1.10) | 274 | (61.9) | 0.66 | (0.51–0.85)* | 349 | (58.0) | 0.70 | (0.56–0.87)* | 9 | (90.0) | 2.55 | (0.30–21.85) |
| Daily labourer/pieceworker | 4 | (50.0) | 1.20 | (0.25–5.81) | 49 | (62.8) | 0.76 | (0.46–1.26) | 205 | (63.1) | 0.88 | (0.67–1.16) | 55 | (85.9) | 1.93 | (0.90–4.15) |
| Merchant/shop owner | 3 | (25.0) | 0.25 | (0.06–1.08) | 30 | (53.6) | 0.55 | (0.31–0.98)* | 33 | (60.0) | 1.08 | (0.6–1.95) | 83 | (76.9) | 1.94 | (1.19–3.18)* |
| Health worker | 4 | (50.0) | 1.11 | (0.24–5.10) | 8 | (50.0) | 0.50 | (0.17–1.42) | 5 | (83.3) | 4.70 | (0.48–45.97) | 10 | (76.9) | 1.60 | (0.40–6.40) |
| Government/civil servant | 13 | (48.1) | 0.83 | (0.32–2.19) | 35 | (74.5) | 1.16 | (0.58–2.33) | 15 | (88.2) | 5.02 | (1.07–23.47)* | 61 | (69.3) | 0.91 | (0.55–1.52) |
| Private sector employee | 3 | (50.0) | 0.66 | (0.11–3.95) | 21 | (67.7) | 0.91 | (0.41–2.02) | 20 | (80.0) | 3.38 | (1.19–9.58)* | 107 | (73.8) | 1.11 | (0.73–1.70) |
| Hawker/market seller | 6 | (42.9) | 1.05 | (0.30–3.67) | 102 | (71.8) | 1.00 | (0.67–1.51) | 121 | (73.8) | 1.56 | (1.05–2.34)* | 181 | (75.1) | 1.20 | (0.86–1.69) |
| Student | 42 | (47.2) | 0.61 | (0.30–1.23) | 70 | (73.7) | 1.16 | (0.70–1.91) | 54 | (68.4) | 1.15 | (0.69–1.94) | 88 | (79.3) | 0.94 | (0.56–1.58) |
| Unemployed | 34 | (54.0) | 1 | (ref) | 719 | (72.2) | 1 | (ref) | 712 | (65.4) | 1 | (ref) | 859 | (71.9) | 1 | (ref) |
| Other occupation | 0 | (0.0) | -- | -- | 102 | (63.0) | 0.76 | (0.53–1.10) | 37 | (68.5) | 1.24 | (0.66–2.33) | 129 | (79.6) | 1.34 | (0.87–2.06) |
| Prior COVID-19 | ||||||||||||||||
| No | 678 | (43.3) | 1 | (ref) | 1389 | (68.4) | 1 | (ref) | 1525 | (64.2) | 1 | (ref) | 1518 | (73.9) | 1 | (ref) |
| Yes | 28 | (66.7) | 3.06 | (1.55–6.07)* | 28 | (66.7) | 0.95 | (0.48–1.89) | 22 | (71.0) | 1.68 | (0.72–2.95) | 52 | (81.2) | 1.25 | (0.64–2.45) |
| Household COVID-19 | ||||||||||||||||
| No | 684 | (43.5) | 1 | (ref) | 1379 | (68.5) | 1 | (ref) | 1451 | (63.8) | 1 | (ref) | 1458 | (73.5) | 1 | (ref) |
| Yes | 17 | (47.2) | 1.20 | (0.60–2.38) | 31 | (63.3) | 0.95 | (0.51–1.77) | 36 | (75.0) | 1.45 | (0.71–2.95) | 112 | (81.8) | 1.19 | (0.75–1.91) |
| Close COVID-19 contact† | ||||||||||||||||
| No | 629 | (43.7) | 1 | (ref) | 1348 | (69.0) | 1 | (ref) | 1277 | (64.1) | 1 | (ref) | 1365 | (73.3) | 1 | (ref) |
| Yes | 11 | (36.7) | 0.93 | (0.42–2.05) | 32 | (61.5) | 0.80 | (0.44–1.46) | 41 | (66.1) | 0.95 | (0.53–1.67) | 140 | (79.5) | 1.10 | (0.73–1.66) |
| COVID-19 vaccination‡ | ||||||||||||||||
| No | 396 | (36.4) | 1 | (ref) | 1057 | (64.7) | 1 | (ref) | 1164 | (60.5) | 1 | (ref) | 1379 | (72.4) | 1 | (ref) |
| Yes | 299 | (58.5) | 1.76 | (1.40–2.21)* | 363 | (80.3) | 1.48 | (1.13–1.93)* | 381 | (78.4) | 1.40 | (1.09–1.80)* | 208 | (88.1) | 1.97 | (1.29–3.02)* |
| HIV status | ||||||||||||||||
| Negative | 767 | (44.0) | 1 | (ref) | 1212 | (67.5) | 1 | (ref) | 1404 | (65.4) | 1 | (ref) | 1388 | (75.3) | 1 | (ref) |
| Positive | 16 | (33.3) | 0.83 | (0.43–1.59) | 203 | (72.8) | 1.42 | (1.05–1.90)* | 113 | (52.6) | 0.77 | (0.57–1.05) | 104 | (63.4) | 0.87 | (0.60–1.26) |
aOR = adjusted odds ratio (adjusted for enrollment month); CI = confidence interval.
†Close contact defined as being within 2 meters of someone outside the household suspected or confirmed to have COVID-19 for greater than 15 minutes
‡≥1 dose of any COVID-19 vaccine.
*p-value<0.05