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Volume 27, Number 8—August 2021
Dispatch

SARS-CoV-2 Prevalence among Outpatients during Community Transmission, Zambia, July 2020

Jonas Z. HinesComments to Author , Sombo Fwoloshi, Davies Kampamba, Danielle T. Barradas, Dabwitso Banda, James E. Zulu, Adam Wolkon, Samuel Yingst, Mary Adetinuke Boyd, Mpanji Siwingwa, Lameck Chirwa, Muzala Kapina, Nyambe Sinyange, Victor Mukonka, Kennedy Malama, Lloyd B. Mulenga, and Simon Agolory
Author affiliations: US Centers for Disease Control and Prevention, Lusaka, Zambia (J.Z. Hines, D.T. Barradas, A. Wolkon, S. Yingst, M.A. Boyd, S. Agolory); University Teaching Hospital, Lusaka (S. Fwoloshi, D. Kampamba, M. Siwingwa, L. Chirwa, L.B. Mulenga); Zambia Ministry of Health, Lusaka (S. Fwoloshi, K. Malama, L.B. Mulenga); Zambia Field Epidemiology Training Program, Lusaka (D. Banda, J.E. Zulu); Zambia National Public Health Institute, Lusaka (M. Kapina, N. Sinyange, V. Mukonka)

Main Article

Table 1

Severe acute respiratory syndrome coronavirus 2 prevalence measured by PCR and ELISA and prevalence ratios in study of prevalence among outpatients during community transmission, Zambia, July 2020

Characteristic Overall proportion, n = 1,952
rPCR-measured prevalence, n = 1,490
ELISA-measured prevalence,† n = 1,657
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.

Main Article

Page created: May 14, 2021
Page updated: July 18, 2021
Page reviewed: July 18, 2021
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