Table 3.
Oral cholera vaccine effectiveness for two doses, versus none, in rural Haiti, complete case analyses
| Cases n (%) |
Controls n (%) |
Crude RR [95% CI] |
Adjusted RR [95% CI] |
Adjusted vaccine effectiveness, % [95% CI] |
p-value | |
|---|---|---|---|---|---|---|
| Cholera vaccine effectiveness case-control study | N=181 | N=716 | ||||
| Self-reported vaccination | 71 (39) | 423 (59) | 0.32 [0.21 – 0.49] | 0.27 [0.16 – 0.45]a | 73 [55 – 84] | <0.0001 |
| Verified vaccination | 28 (15) | 198 (28) | 0.30 [0.17 – 0.51] | 0.26 [0.13 – 0.51]a | 74 [49 – 87] | <0.0001 |
| Bias-indicator case-control study | N=157 | N=625 | ||||
| Self-reported vaccination | 84 (54) | 385 (62) | 0.62 [0.39 – 0.99] | 0.62 [0.37 – 1.03]b | 38 [−3 – 63] | 0.07 |
| Verified vaccination | 42 (27) | 192 (31) | 0.70 [0.41 – 1.19] | 0.71 [0.39 – 1.29]b | 29 [−29 – 61] | 0.26 |
| Test negative design | N=181 | N=157 | ||||
| Self-reported vaccination | 71 (39) | 84 (54) | 0.51 [0.32, 0.81] | 0.26 [0.12 – 0.61]c | 74 [39 – 88] | 0.002 |
| Verified vaccination | 28 (15) | 42 (27) | 0.49 [0.29, 0.84] | 0.38 [0.12 – 1.16]c | 62 [−16 – 88] | 0.09 |
N=875; Adjusted for matching factors (location of residence, enrollment time, age group) via conditional logistic regression and the following covariates: female sex, age (continuous), respondent was self, ever attended school, main toilet is latrine, reports knowing how to treat water, reports always treating water, household buys water, water source (from pump, treated water, bottled water, rain water, well), water treatment method (tablets, boiling, chlorine), same water source used for washing and drinking, makes a living by agriculture, makes a living by fishing, consumed food or beverage outside of home in the last week, ate raw fruits or vegetables in the last week, knowledge on how to avoid cholera (heating food, not going to the bathroom near water source, “other” way not included in list), hand washing habits (before and after touching a baby, at “other” time not included in list), member of household had diarrhea in last 7 days, water vessel cover (uncovered, covered, partially covered), water vessel has a tap, size of opening on water vessel (narrow versus wide), 30 minutes or more on foot from home to river
N=770; Adjusted for same variables listed above.
N=310; Adjusted for female sex, age (continuous), respondent was self, ever attended school, household has electricity, catchment area (first vaccination campaign versus second), water source (from tap, river), water treatment method (tablets, “other” way not included in list), must leave house to get water, same water source used for washing and drinking, antacid usage in the past 14 days, ate leftover unheated rice in past week, ate raw fruits or vegetables in the last week, knowledge on how to avoid cholera (heating food, treating water), hand washing habits (after using toilet, before eating), previous hospitalization for diarrhea, prior admission to a cholera treatment unit, member of household had diarrhea in last 7 days, member of household previously admitted to cholera treatment unit, length of current admission to health facility (days), volume of intravenous fluid provided at clinic, volume of oral rehydration salts provided at clinic, dehydration stage (A, B or C), reports washing hands 4 or more times per day, reports knowing cholera can be transmitted through uncooked food.