Results from Geographical Analysis in Vaccine Trials
Cholera risk (per 1,000 persons) by level of vaccine coverage
|
Level of vaccine coverage (%)‡ |
Target population
|
Vaccinees |
Placebo recipients |
||||
|
N |
Cases |
Risk per 1,000 persons* |
N |
Cases |
Risk per 1,000 persons† |
||
|
≤30.61 |
24,295 |
5,506 |
16 |
2.90 |
2,741 |
21 |
7.66 |
|
30.62-40.02 |
24,181 |
8,625 |
14 |
1.62 |
4,284 |
24 |
5.60 |
|
40.03-44.96 |
24,230 |
10,254 |
21 |
2.04 |
5,253 |
22 |
4.18 |
|
44.97-50.63 |
24,300 |
11,701 |
29 |
2.47 |
5,889 |
26 |
4.41 |
|
50.64+ |
24,143 |
13,250 |
16 |
1.20 |
6,500 |
15 |
2.30 |
|
Total |
121,149 |
49,336 |
96 |
1.94 |
24,667 |
108 |
4.37 |
* P=.03 for trend
† P<.001 for trend
‡ Baris are arranged by vaccine coverage into quintiles, each having approximately the same age- and gender-eligible population.
This table shows the risk of cholera by level of cholera vaccine coverage calculated through the environmental connectivity analysis (e.g., whether a bari was linked to other baris by ponds within 500 meters). The risk of cholera in recipients of two or three doses of either vaccine or placebo was inversely related to the level of vaccine coverage. This trend was significant in both placebo (p=<0.001) and vaccine recipients (p=0.03). The difference between the risk of cholera in the highest and lowest quintiles for environmental vaccine coverage was larger for placebo recipients than for vaccine recipients.
