Volume 27, Number 5—May 2021
Research
Herd Immunity against Severe Acute Respiratory Syndrome Coronavirus 2 Infection in 10 Communities, Qatar
Table 2
Characteristic | No. (%)† tested | SARS-CoV-2 seropositive |
Univariable regression analysis‡ |
||||
---|---|---|---|---|---|---|---|
No. | %§ (95% CI) | p value | OR (95% CI) | p value¶ | |||
Sex | |||||||
M | 240 (94.1) | 189 | 78.8 (73.0–83.7) | <0.001 | Referent | ||
F |
15 (5.9) |
4 |
26.7 (7.8–55.1) |
0.10 (0.03–0.32) |
<0.001 |
||
Age, y | |||||||
<29 | 105 (41.2) | 84 | 80.0 (71.1–87.2) | 0.322 | Referent | ||
30–39 | 111 (43.5) | 83 | 74.8 (65.6–82.5) | 0.74 (0.39–1.41) | 0.360 | ||
40–49 | 27 (10.6) | 19 | 70.4 (49.8–86.2) | 0.59 (0.23–1.54) | 0.284 | ||
>50 |
12 (4.7) |
7 |
58.3 (27.7–84.8) |
0.35 (0.10–1.21) |
0.098 |
||
Nationality | |||||||
Other# | 48 (18.8) | 23 | 47.9 (33.3–62.8) | <0.001 | Referent | ||
Indian | 32 (12.5) | 20 | 62.5 (43.7–78.9) | 1.81 (0.73–4.51) | 0.202 | ||
Nepalese | 157 (61.6) | 132 | 84.1 (77.4–89.4) | 5.74 (2.82–11.67) | <0.001 | ||
Bangladeshi |
18 (7.1) |
18 |
100.0 (81.5–100.0) |
Omitted by model |
NA |
||
Education level | |||||||
Intermediate or lower | 101 (39.6) | 88 | 87.1 (79.0–93.0) | <0.001 | Referent | ||
Secondary/high school/vocational | 80 (31.4) | 69 | 86.3 (76.7–92.9) | 0.93 (0.39–2.20) | 0.863 | ||
University | 27 (10.6) | 17 | 63.0 (42.4–80.6) | 0.25 (0.09–0.67) | 0.005 | ||
Missing |
47 (18.4) |
19 |
40.4 (26.4–55.7) |
0.10 (0.04–0.23) |
<0.001 |
||
Contact with an infected person | |||||||
No | 124 (48.6) | 93 | 75.0 (66.4–82.3) | 0.303 | Referent | ||
Yes | 14 (5.5) | 13 | 92.9 (66.1–99.8) | 4.33 (0.54–34.48) | 0.166 | ||
Unknown/missing |
117 (45.9) |
87 |
74.4 (65.5–82.0) |
0.97 (0.54–1.73) |
0.909 |
||
Symptoms in the past 2 weeks** | |||||||
Asymptomatic | 184 (72.2) | 148 | 80.4 (74.0–85.9) | <0.001 | Referent | ||
1 | 16 (6.3) | 16 | 100.0 (79.4–100.0) | Omitted by model | NA | ||
>2 | 12 (4.7) | 12 | 100.0 (73.5–100.0) | Omitted by model | NA | ||
Missing |
43 (16.9) |
17 |
39.5 (25.0–55.6) |
0.16 (0.08–0.32) |
<0.001 |
||
Symptoms required medical attention | |||||||
No | 210 (82.4) | 174 | 82.9 (77.1–87.7) | <0.001 | Referent | ||
Yes | 3 (1.2) | 3 | 100.0 (29.2–100.0) | Omitted by model | NA | ||
Unknown/missing | 42 (16.5) | 16 | 38.1 (23.6–54.4) | 0.13 (0.06–0.26) | <0.001 |
*CMW, craft and manual worker; NA, not applicable; OR, odds ratio; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. †Percentage of total sample. ‡Overall sample size and numbers per stratum were too small to warrant conduct of meaningful multivariable regression analysis. §Percent seropositive of those tested. ¶Covariates with p <0.05 in univariable analysis (i.e., sex, nationality, and education level were considered as showing evidence for an association with SARS-CoV-2 seropositivity. #Includes all other nationalities that contributed <10% of the sample. These are Filipino, Georgian, Kenyan, Sri Lankan, and Tunisian. **Symptoms were based on self-report and included fever, chills, muscle ache/myalgia, sore throat, cough, runny nose/rhinorrea, shortness of breath, wheezing, chest pain, other respiratory symptoms, headache, nausea and vomiting, abdominal pain, diarrhea, loss of sense of smell, and loss of sense of taste.