Attack percentage by BTS treatment step and age group (in brackets when subgroup size less than 100)
| BTS treatment step | Age group (years) | |||||
|---|---|---|---|---|---|---|
| <5 | 5–15 | 16–44 | 45–74 | 75+ | Overall | |
| 0 | (9) | 4 | 4 | 10 | (14) | 6 |
| 1 | 30 | 13 | 9 | 12 | (16) | 13 |
| 2 | 34 | 22 | 18 | 18 | 18 | 20 |
| 3 | 48 | 21 | 28 | 22 | 25 | 25 |
| 4 | (55) | 35 | 42 | 41 | (41) | 40 |
| 5 | (50) | (60) | (68) | 50 | (63) | 56 |
| Overall | 37 | 21 | 19 | 23 | 27 | 22 |