Table 2.
Number of Included Studies by Study Design, Ring Type, and Study Setting
| Study Setting | ||||||||
|---|---|---|---|---|---|---|---|---|
|
Endemic Setting
(n = 12 a ) |
EpidemicSetting
(n = 15) |
Emerging Infection, Emergency, and Outbreak
(n = 18 b ) |
EliminationSetting
(n = 7) |
|||||
| Study Characteristic | No. | % | No. | % | No. | % | No. | % |
| Trial design | ||||||||
| Cluster-randomized trial | 5 | 45 | 2 | 13 | 1 | 8 | 7 | 100 |
| Ring-stratified cluster-randomized trial | 0 | 0 | 4 | 27 | 1 | 8 | 0 | 0 |
| Ring trial | 6 | 55 | 9 | 60 | 11 | 84 | 0 | 0 |
| Ring typec | ||||||||
| Household including index case | 8 | 73 | 14 | 93 | 10 | 67 | 1 | 14 |
| Neighborhood around index case | 2 | 18 | 0 | 0 | 1 | 7 | 7 | 100 |
| Contacts of index case | 1 | 9 | 2 | 13 | 3 | 20 | 0 | 0 |
a Only 11 studies provided sufficient information to determine trial design and ring type.
b Only 13 studies provided sufficient information to determine trial design, and 15 provided sufficient information to determine ring type.
c If multiple types of rings were used, column percentages exceed 100%.