Table 2 Crude, weighted, and weighted and age-standardized seroprevalence based on varying seropositivity classification algorithms
Seropositivity combinations | Crude proportion (%), n = 2865 | Weighted proportion (%) with 95% CI, n = 2858 | Weighted & age-standardized (BGS98) proportion (%) with 95% CI, n = 2858 | Weighted & age-standardized (DEGS) proportion (%) with 95% CI, n = 2858 |
|---|---|---|---|---|
IgG seropositivity | ||||
IgG positivity–ELISA borderline or positive & positive immunoblota | 2.4 | 2.2 (1.6, 2.7) | 1.8 (1.4, 2.3) | 2.2 (1.6, 2.7) |
IgG positivity–positive ELISA | 6.8 | 6.4 (5.5, 7.3) | 6.0 (5.1, 6.9) | 6.5 (5.6, 7.4) |
IgG positivity–positive ELISA & borderline or positive immunoblot or borderline ELISA & positive immunoblotb | 4.8 | 4.6 (3.8, 5.3) | 4.2 (3.4, 4.9) | 4.7 (3.9, 5.4) |
IgM seropositivity | ||||
IgM positivity–ELISA borderline or positive & positive immunoblota | 0.6 | 0.6 (0.3, 0.9) | 0.6 (0.3, 0.8) | 0.6 (0.3, 0.8) |
IgM positivity–positive ELISA | 1.0 | 1.0 (0.6, 1.3) | 0.9 (0.5, 1.2) | 1.0 (0.6, 1.3) |
IgM positivity–positive ELISA & borderline or positive immunoblot or borderline ELISA & positive immunoblotb | 0.7 | 0.6 (0.3, 0.9) | 0.6 (0.3, 0.9) | 0.6 (0.4, 0.9) |
IgG and IgM seropositivity combined | ||||
IgG positivity & IgM positivity–ELISA borderline or positive & positive immunoblota | 0.1 | < 0.1 (0.0, 0.2) | 0.1 (0.0, 0.3) | 0.1 (0, 0.2) |
IgG positivity & IgM positivity–positive ELISA | 0.4 | 0.5 (0.2, 0.7) | 0.4 (0.2, 0.7) | 0.5 (0.2, 0.8) |
IgG positivity & IgM positivity–positive ELISA & borderline or positive immunoblot or borderline ELISA & positive immunoblotb | 0.2 | 0.3 (0.1, 0.5) | 0.3 (0.1, 0.5) | 0.3 (0.1, 0.5) |