Table 2.
Euvichol® vaccine effectiveness in a case-control study in Haiti, 2018-2020a.
| VE case-control | Cases (N = 15) | Controls (N = 60) | Crude RR (95% CI)b | Crude VE (95% CI)b | Adjusted RR (95% CI)c | Adjusted VE (95% CI)c |
|---|---|---|---|---|---|---|
| Number of doses | ||||||
| Two | 4 (26.7%) | 31 (51.7%) | 0.23 (0.05-1.12) | 77% (-12 - 95%) | 0.31 (0.06 - 1.71) | 69% (-71 - 94%) |
| One | 4 (26.7%) | 12 (20.0%) | 0.78 (0.17 - 3.66) | 22% (-266 - 83%) | 1.9 (0.28 - 12.4) | -90% (-1140 - 72%) |
| None | 7 (46.7%) | 17 (28.3%) | Ref | Ref | Ref | Ref |
| Vaccination card availabled | 0/8 (0%) | 6/43 (14.0%) |
| Bias-indicator case-control | Cases (N = 63) | Controls (N = 249) | Crude RR (95% CI)b | Crude VE (95% CI)b | Adjusted RR (95% CI)e | Adjusted VE (95% CI)e |
|---|---|---|---|---|---|---|
| Number of doses | ||||||
| Two | 17 (27.0%) | 86 (34.5%) | 0.62 (0.30 - 1.26) | 38% (-26 - 70%) | - | - |
| One | 12 (19.0%) | 43 (17.3%) | 0.95 (0.44 - 2.05) | 5% (-105 - 56%) | - | - |
| None | 34 (54.0%) | 120 (48.2%) | Ref | Ref | - | - |
| Vaccination card availabled | 1/29 (3.4%) | 10/129 (7.8%) |
CI, confidence interval; RR, relative risk; Ref, reference; VE, vaccine effectiveness.
a
Doses of vaccines are by self-report.
b
Adjusted for matching factors (age and gender).
c
Adjusted for matching factors (age and gender) and whether the participant attended school.
d
Number of individuals who provided a vaccination card for review among individuals who reported receiving the vaccine.
e
Adjusted analyses were not performed given that no factors were associated with both cholera and vaccination at our prespecified threshold.