Serotype-specific attack rates
| Invasive serotypes, n (per 100 000 per year) | Less invasive serotypes, n (per 100 000 per year) | |
| 16–44 | 28 (5.3) | 17 (3.2) |
| 45–64 | 34 (12.1) | 21 (7.5) |
| 65–74 | 17 (16.7) | 29 (28.4) |
| 75–84 | 21 (30.7) | 36 (52.6) |
| 85+ | 7 (30.9) | 32 (141.5) |
Invasive serotypes include 1, 5, 7F and 8.