Volume 27, Number 8—August 2021
Dispatch
SARS-CoV-2 Prevalence among Outpatients during Community Transmission, Zambia, July 2020
Table 1
Characteristic | Overall proportion, n = 1,952 |
rPCR-measured prevalence, n = 1,490 |
ELISA-measured prevalence,† n = 1,657 |
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---|---|---|---|---|---|---|---|---|---|---|
No. (%) |
95% CI | % (95% CI) |
PR | % (95% CI) | PR | |||||
Overall |
1,952 |
NA |
13.4 (8.3–18.5) |
Not applicable |
8.2 (5.1–11.4) |
Not applicable |
||||
Sex | ||||||||||
M | 767 (39.4) | 35.4–43.5 | 14.5 (8.9–20.0) | Referent | 8.1 (5.0–11.2) | Referent | ||||
F |
1,178 (60.6) |
56.5–64.6 |
12.8 (7.1–18.5) |
0.9 (0.7–1.1) |
6.8 (3.6–10.0) |
0.8 (0.6–1.2) |
||||
Age range, y | ||||||||||
0–9 | 41 (2.1) | 0.9–3.4 | 6.3 (0.0–16.0) | Referent | 13.0 (0.0–28.5) | Referent | ||||
10–19 | 161 (8.3) | 6.0–10.6 | 8.2 (1.7–14.7) | 1.3 (0.3–5.0) | 11.0 (1.2–20.9) | 0.9 (0.3–2.7) | ||||
20–29 | 628 (32.3) | 28.5–36.2 | 14.0 (7.1–20.9) | 2.2 (0.7–7.3) | 5.3 (2.0–8.6) | 0.4 (0.2–1.0) | ||||
30–39 | 488 (25.1) | 22.7–27.6 | 15.4 (9.9–20.9) | 2.5 (0.7–8.5) | 5.7 (2.3–9.0) | 0.4 (0.2–1.3) | ||||
40–49 | 293 (15.1) | 12.0–18.1 | 13.2 (7.7–18.8) | 2.1 (0.6–7.2) | 8.4 (4.0–12.8) | 0.7 (0.2–2.2) | ||||
50–59 | 185 (9.5) | 7.1–12.0 | 12.2 (5.0–19.4) | 2.0 (0.5–7.8) | 10.2 (2.4–17.9) | 0.8 (0.3–2.2) | ||||
60–69 | 83 (4.3) | 2.9–5.7 | 14.7 (5.6–23.8) | 2.4 (0.6–9.4) | 6.5 (0.0–13.7) | 0.5 (0.1–2.3) | ||||
≥70 |
64 (3.3) |
2.0–4.6 |
11.1 (3.7–18.5) |
1.8 (0.4–7.1) |
15.6 (2.0–29.1) |
1.2 (0.3–5.0) |
||||
District | ||||||||||
Kabwe | 249 (12.8) | 0.0–28.2 | 3.8 (1.6–6.1) | 0.2 (0.1–0.4) | 3.0 (2.0–4.1) | 0.3 (0.2–0.5) | ||||
Livingstone | 307 (15.8) | 0.0–35.8 | 23.4 (15.5–31.4) | 1.3 (0.8–1.9) | 3.9 (1.4–6.4) | 0.4 (0.2–0.8) | ||||
Lusaka | 639 (32.8) | 8.6–57.1 | 18.8 (13.1–24.4) | Referent | 9.9 (5.5–14.4) | Referent | ||||
Nakonde | 160 (8.2) | 0.0–20.4 | 7.0 (4.5–9.4) | 0.4 (0.2–0.6) | 16.4 (2.5–30.3) | 1.6 (0.7–4.0) | ||||
Ndola | 288 (14.8) | 0.0–31.9 | 14.1 (0.0–28.7) | 0.8 (0.3–2.0) | 4.8 (2.3–7.4) | 0.5 (0.3–0.9) | ||||
Solwezi |
304 (15.6) |
0.0–33.6 |
6.0 (2.2–9.8) |
0.3 (0.2–0.6) |
4.3 (0.6–8.0) |
0.4 (0.2–1.0) |
||||
Education | ||||||||||
Primary | 476 (24.7) | 19.7–29.6 | 10.5 (5.6–15.4) | Referent | 5.2 (1.3–9.1) | Referent | ||||
Secondary | 918 (47.6) | 39.6–55.5 | 12.7 (7.7–17.7) | 1.2 (1.0–1.5) | 8.0 (3.6–12.5) | 1.5 (0.7–3.4) | ||||
Higher | 443 (23.0) | 13.6–32.3 | 18.4 (9.6–27.1) | 1.8 (1.1–2.9) | 8.1 (3.6–12.6) | 1.6 (0.7–3.3) | ||||
None | 90 (4.7) | 2.9–6.5 | 11.1 (1.6–20.6) | 1.1 (0.6–1.8) | 7.2 (0.0–14.8) | 1.4 (0.6–3.5) | ||||
Don't know |
3 (0.2) |
0.0–0.4 |
0.0 |
Not calculated |
0.0 (0.0–0.0) |
Not calculated |
||||
Health facility type | ||||||||||
Hospital | 1,127 (57.9) | 33.7–82.1 | 16.3 (9.5–23.0) | 1.7 (0.8–3.4) | 7.8 (4.4–11.1) | 1.2 (0.6–2.6) | ||||
Tertiary hospital | 260 (13.4) | 0.0–29.6 | 8.2 (1.7–14.7) | Not calculated | 9.0 (1.6–16.3) | Not calculated | ||||
Referral hospital | 381 (19.6) | 0.0–41.8 | 16.3 (2.0–30.6) | Not calculated | 4.6 (4.4–4.8) | Not calculated | ||||
Community hospital | 486 (25.0) | 1.8–48.1 | 21.3 (16.3–26.4) | Not calculated | 9.2 (4.2–14.2) | Not calculated | ||||
Health center | 820 (42.1) | 17.9–66.4 | 9.7 (3.3–16.0) | Referent | 6.4 (1.8–11.1) | Referent | ||||
Urban health center | 738 (37.9) | 14.4–61.4 | 9.8 (2.7–17.0) | Not calculated | 6.1 (0.9–11.4) | Not calculated | ||||
Rural health center |
82 (4.2) |
0.0–13.1 |
8.2 (8.2–8.2) |
Not calculated |
8.7 (1.3–16.0) |
Not calculated |
||||
Reason for visit | ||||||||||
Fever or respiratory | 548 (28.2) | 22.8–33.5 | 12.9 (6.6–19.2) | 1.0 (0.6–1.7) | 9.0 (3.5–14.4) | 1.8 (1.0–3.1) | ||||
COVID-19 testing | 45 (2.3) | 0.0–4.7 | 27.5 (17.7–37.3) | 2.2 (1.3–3.9) | 0.0 (0.0–0.0) | Not calculated | ||||
Other acute complaint | 538 (27.6) | 22.1–33.2 | 10.7 (5.6–15.7) | 0.9 (0.5–1.5) | 7.1 (4.6–9.7) | 1.4 (0.9–2.2) | ||||
Routine health visit | 368 (18.9) | 9.9–27.9 | 12.5 (4.6–20.3) | Referent | 5.0 (2.0–8.1) | Referent | ||||
Not stated |
448 (23.0) |
15.3–30.0 |
15.5 (9.8–21.2) |
1.2 (0.7–2.3) |
7.5 (2.6–12.4) |
1.5 (0.8–2.9) |
||||
Medical history‡ | ||||||||||
Any underlying condition | 664 (34.1) | 29.6–38.7 | 11.4 (5.6–17.1) | 0.8 (0.6–1.1) | 7.3 (4.3–10.3) | 1.0 (0.7–1.4) | ||||
HIV | 247 (12.8) | 9.8–15.8 | 13.3 (4.3–22.4) | 1.0 (0.6–1.5) | 4.6 (1.3–8.0) | 0.6 (0.3–1.2) | ||||
Currently pregnant¶ | 118 (12.5) | 7.9–17.0 | 13.4 (3.3–23.5) | 1.1 (0.7–1.9) | 4.7 (0.0–11.9) | 0.7 (0.2–2.6) | ||||
Hypertension | 196 (10.1) | 7.6–12.5 | 14.1 (6.9–21.3) | 1.1 (0.8–1.4) | 7.7 (1.2–14.2) | 1.1 (0.5–2.3) | ||||
Malaria | 143 (7.4) | 3.2–11.6 | 4.8 (0.8–8.7) | 0.3 (0.2–0.7) | 11.1 (3.5–18.7) | 1.5 (0.8–2.7) | ||||
Asthma | 51 (2.6) | 1.9–3.3 | 13.9 (0.0–28.0) | 1.0 (0.4–2.8) | 3.8 (0.0–11.2) | 0.5 (0.1–3.4) | ||||
Diabetes | 50 (2.6) | 1.4–3.8 | 12.8 (1.8–23.9) | 1.0 (0.5–1.9) | 10.9 (0.0–24.8) | 1.5 (0.5–4.7) | ||||
Immunocompromised | 48 (2.5) | 0.4–4.5 | 25.9 (0.0–54.8) | 2.0 (0.9–4.3) | 9.7 (0.0–24.5) | 1.3 (0.3–5.5) | ||||
Tuberculosis | 36 (1.9) | 1.1–2.6 | 14.8 (2.4–27.2) | 1.1 (0.5–2.4) | 6.0 (0.0–18.5) | 0.8 (0.1–4.8) | ||||
Cardiac disease | 29 (1.5) | 0.4–2.6 | 8.0 (0.2–15.8) | 0.6 (0.2–1.6) | 20.3 (0.0–41.5) | 2.9 (1.2–6.7) | ||||
Chronic kidney disease | 10 (0.5) | 0.1–0.9 | 0.0 | Not calculated | 0.0 | Not calculated | ||||
Emphysema/COPD | 5 (0.3) | 0.0–0.7 | 0.0 | Not calculated | 0.0 | Not calculated | ||||
Cancer | 5 (0.3) | 0.0–0.7 | 0.0 | Not calculated | 0.0 | Not calculated | ||||
Cirrhosis or fatty liver | 1 (0.1) | 0.0–0.2 | 0.0 | Not calculated | 0.0 | Not calculated | ||||
Other chronic condition | 83 (4.5) | 2.3–6.6 | 6.8 (0.6–13.0) | 0.5 (0.2–1.1) | 11.3 (2.1–20.5) | 1.5 (0.7–3.1) | ||||
Don't know |
357 (18.3) |
10.8–25.9 |
13.4 (6.8–20.1) |
1.0 (0.6–1.6) |
6.7 (3.0–10.3) |
0.9 (0.5–1.5) |
||||
Contact with a confirmed case of COVID-19 | ||||||||||
No | 1,704 (87.7) | 83.0–92.5 | 12.4 (7.7–17.2) | Referent | 7.1 (4.3–10.0) | Referent | ||||
Yes | 42 (2.2) | 0.4–3.9 | 20.0 (2.6–37.5) | 1.6 (0.8–3.4) | 16.4 (6.5–26.3) | 2.3 (1.4–3.8) | ||||
Don't know |
196 (10.1) |
5.8–14.4 |
18.9 (10.4–27.4) |
1.5 (1.2–1.9) |
6.9 (2.4–11.3) |
1.0 (0.6–1.7) |
||||
Travel | ||||||||||
International | 15 (0.8) | 0.3–1.2 | 35.7 (8.4–63.0) | 2.7 (1.5–4.8) | 0.0 | Not calculated | ||||
Domestic | 313 (16.3) | 11.3–21.4 | 12.4 (7.4–17.3) | 0.9 (0.6–1.3) | 4.5 (0.6–8.4) | 0.6 (0.2–1.5) | ||||
None | 1,547 (80.7) | 75.9–85.6 | 13.4 (7.6–19.1) | Referent | 7.9 (4.4–11.5) | Referent | ||||
Don't know |
41 (2.1) |
0.0–4.7 |
7.7 (0.0–19.3) |
0.6 (0.1–2.4) |
0.0 |
Not calculated |
||||
In-person work attendance, past month | ||||||||||
No | 1,448 (75.3) | 68.4–82.1 | 12.6 (7.9–17.2) | Referent | 7.3 (4.1–10.6) | Referent | ||||
Yes | 426 (22.1) | 14.6–29.7 | 16.0 (6.0–26.0) | 1.3 (0.8–2.0) | 8.5 (3.4–13.7) | 1.2 (0.7–2.1) | ||||
Don't know |
50 (2.6) |
0.0–5.5 |
18.2 (1.4–35.0) |
1.4 (0.6–3.4) |
0.0 |
Not calculated |
||||
Visits to the market, past month | ||||||||||
0–1 | 400 (22.2) | 17.0–27.4 | 8.8 (3.6–14.0) | Referent | 10.6 (5.4–15.7) | Referent | ||||
≥2 |
1401 (77.8) |
72.6–83.0 |
14.4 (8.5–20.3) |
1.6 (1.1–2.5) |
6.5 (3.7–9.3) |
0.6 (0.5–0.8) |
||||
Usual transportation | ||||||||||
Car | 178 (9.3) | 4.6–13.9 | 18.6 (12.4–24.7) | 1.5 (1.0–2.2) | 14.8 (5.8–23.7) | 2.3 (1.1–4.7) | ||||
Taxi | 215 (11.2) | 4.8–17.5 | 15.5 (1.4–29.6) | 1.2 (0.6–2.5) | 4.9 (1.1–8.7) | 0.8 (0.3–1.8) | ||||
Bike | 63 (3.3) | 1.3–5.3 | 4.7 (0.0–11.6) | 0.4 (0.1–1.6) | 6.8 (0.0–20.7) | 1.1 (0.2–5.5) | ||||
Minibus | 511 (26.6) | 15.1–38.1 | 12.3 (7.4–17.2) | 1.0 (0.6–1.5) | 7.7 (5.0–10.5) | 1.2 (0.7–2.0) | ||||
Walking | 938 (48.8) | 39.3–58.3 | 12.8 (6.7–18.9) | Referent | 6.4 (2.6–10.2) | Referent | ||||
Don't know | 17 (0.9) |
0.0–1.8 | 25.0 (0.0–59.2) |
2.0 (0.6–6.8) | 0.0 | Not calculated |
*COPD, chronic obstructive pulmonary disease; COVID-19, coronavirus disease; NA, not applicable; PR, prevalence ratio; rPCR, real-time PCR †ELISA prevalence estimates and 95% CIs were adjusted for imperfect assay test characteristics (sensitivity 64.2%, specificity 100%). ‡For medical history, “no” responses were omitted from the table. ¶Analysis of pregnancy variable was restricted to women 15–49 y of age, considered the child-bearing age range in the Zambia Demographic Health Surveys and other surveys in Zambia.
Page created: May 14, 2021
Page updated: July 18, 2021
Page reviewed: July 18, 2021
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