Volume 15, Number 10—October 2009
Research
Review of an Influenza Surveillance System, Beijing, People’s Republic of China
Peng Yang, Wei Duan, Min Lv, Weixian Shi, Xiaoming Peng, Xiaomei Wang, Yanning Lu, Huijie Liang, Holly Seale, Xinghuo Pang, and Quanyi Wang
Table 2
Onset of influenza epidemic as determined by the various ILI data during the 2007–08 influenza season, Beijing, People’s Republic of China*
| Data | ILI rate |
ILI count |
|||
|---|---|---|---|---|---|
| Warnings meeting the standard | Onset week | Warnings meeting the standard | Onset week | ||
| Hospital level | |||||
| 1 | C1 in a given week and the greater following value | 51 | C1 in a given week and the greater following value | 51 | |
| 2 | Consecutive 2 C2 | 51 | Consecutive 2 C2 | 49† | |
| 3 |
C1 in a given week and the greater following value |
51 |
Consecutive 3 C3 |
49† |
|
| Age group, y | |||||
| 0–4 | NA | NA | Consecutive 3 C3 | 48 | |
| 5–14 | NA | NA | Consecutive 2 C2 | 46 | |
| 15–24 | NA | NA | C1 in a given week and the greater following value | 49† | |
| 25–59 | NA | NA | C1 in a given week and the greater following value | 49† | |
| >60 | NA | NA | C1 in a given week and the greater following value | 51 | |
*ILI, influenza-like illness; C1, C1-mild algorithm; C2, C2-medium algorithm; C3, C3-ultra algorithm; NA, not available.
†Onset week, determined by the accepted standard based on 40% of the maximum weekly isolation rate, is the threshold
