Volume 22, Number 8—August 2016
Research
Exposure-Specific and Age-Specific Attack Rates for Ebola Virus Disease in Ebola-Affected Households, Sierra Leone
Hilary Bower, Sembia Johnson, Mohamed S. Bangura, Alie Joshua Kamara, Osman Kamara, Saidu H. Mansaray, Daniel Sesay, Cecilia Turay, Francesco Checchi, and Judith R. Glynn
Table 5
Sensitivity analysis showing risk factors associated with development of EVD as a subsequent case-patient in Ebola-affected households, Kerry Town, Sierra Leone, 2014–2015*
| Risk factor | Total, excluding probable cases, N = 764 |
||
|---|---|---|---|
| No. patients/no. total (%)† | Adjusted RR‡ (95% CI) | p value§ | |
| Sex | |||
| M | 114/315 (36.2) | 1.0 (0.83–1.2) | |
| F |
188/449 (41.9) |
1 |
1.0 |
| Age, y | |||
| <2 | 21/50 (42.0) | 0.99 (0.66–1.5) | |
| 2–4 | 22/72 (30.6) | 0.98 (0.68–1.4) | |
| 5–9 | 27/116 (23.3) | 0.69 (0.47–1.0) | |
| 10–14 | 26/106 (24.5) | 0.60 (0.39–0.93) | |
| 15–19 | 34/94 (36.2) | 0.77 (0.52–1.1) | |
| 20–29 | 63/146 (43.2) | 1 | |
| 30–39 | 47/81 (58.0) | 1.2 (0.86–1.6) | |
| 40–49 | 28/44 (63.6) | 1.2 (0.82–1.8) | |
| >50 |
33/53 (62.3) |
1.5 (1.1–2.0) |
0.002 |
| Maximum exposure | |||
| Handled corpse | 60/72 (83.3) | 40.6 (8.5–194.5) | |
| Handled fluids | 65/112 (58.0) | 30.5 (6.4–144.8) | |
| Direct wet contact | 125/276 (45.3) | 24.1 (5.2–113.2) | |
| Direct dry contact | 41/119 (34.5) | 16.7 (3.6–78.1) | |
| Indirect wet contact | 5/19 (26.3) | 17.2 (3.1–94.7) | |
| Indirect dry contact | 4/70 (5.7) | 2.3 (0.37–14.3) | |
| Minimal/no contact |
2/96 (2.1) |
1 |
<0.001 |
| Position in household | |||
| Household head | 22/50 (44.0) | 0.58 (0.35–0.98) | |
| Household member |
280/714 (39.2) |
1 |
0.02 |
| Household size | |||
| >16 | 108/197 (54.8) | 2.6 (0.98–6.7) | |
| 11–15 | 90/282 (31.9) | 1.5 (0.57–3.9) | |
| 6–10 | 96/245 (39.2) | 2.3 (0.89–5.7) | |
| 1–5 | 8/40 (20.0) | 1 | 0.04 |
*Subsequent case-patients were any household members who contracted EVD after the first (primary) case-patient. EVD, Ebola virus disease; RR, risk ratio.
†Excluded data: 4 deaths from uncertain cause; 27 persons with no individual-level data, 97 primary case-patients; 45 case-patients were classified as having EVD on the basis of their histories but had no diagnosis of EVD at the time. Missing data: 2 persons with age unknown.
‡Adjusted for clustering and all variables in the model.
§p values calculated from likelihood ratio test in logistic regression model.
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