Table 5. Overall and indirect vaccine effectiveness against non-cholera diarrhea using ring vaccination strategy.
| Duration of Follow-Up | High Vaccine Coverage Cohorts* (Coverage ≥ 30%) | Low Vaccine Coverage Cohorts* (Coverage ≤ 12%) | VE (95% CI; p-Value) | |||
|---|---|---|---|---|---|---|
| Index Cases/Population † | Number of Cases ‡ (IR/1,000) | Index Cases/Population † | Number of Cases ‡ (IR/1,000) | Crude | Adjusted £ | |
| Overall VE | ||||||
| 2 y | 55/22,344 | 139 (6.22) | 51/21,254 | 154 (7.25) | 14% (−8 to 32; 0.1909) | 10% (−14 to 29; 0.3737) |
| 3 y | 116/46,059 | 341 (7.40) | 95/40,380 | 295 (7.31) | −1% (−18 to 13; 0.8665) | −4% (−22 to 12; 0.6599) |
| 4 y | 156/64,295 | 524 (8.15) | 136/62,287 | 453 (7.27) | −12% (−27 to 1; 0.0748) | −14% (−29 to 0; 0.0508) |
| 5 y | 182/72,978 | 600 (8.22) | 151/68,790 | 496 (7.21) | −14% (−29 to −1; 0.1962) | −16% (−32 to −3; 0.0149) |
| Indirect VE | ||||||
| 2 y | 55/12,998 | 79 (6.08) | 51/20,624 | 149 (7.22) | 16% (−10 to 36; 0.2128) | 10% (−18 to 32; 0.4454) |
| 3 y | 116/27,452 | 228 (8.31) | 95/38,615 | 281 (7.28) | −14% (−36 to 4; 0.1365) | −16% (−39 to 3; 0.1052) |
| 4 y | 156/38,760 | 362 (9.34) | 136/59,207 | 428 (7.23) | −29% (−49 to −12; <0.001) | −30% (−51 to −13; <0.001) |
| 5 y | 182/43,900 | 405 (9.23) | 151/65,299 | 470 (7.20) | −28% (−47 to −12; <0.001) | −29% (−49 to −12; <0.001) |
*The vaccine coverage of individuals living within 25 m of index cases was calculated as the number of two-dose vaccine recipients divided by all population within 25 m.
†Number of index cases over/cumulative total population within 25 m of the index cases.
‡Cumulative total non-cholera diarrhea cases within 25 m of the index cases (excluding index cases) and within 8–28 d of the onset of index case.
£Adjusted for age, sex, and distance to nearest water body.
IR, incidence rate; VE, vaccine effectiveness.