Volume 15, Number 10—October 2009
Research
Review of an Influenza Surveillance System, Beijing, People’s Republic of China
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