TABLE 4. CDC novel influenza virus pandemic intervals.
| Intervals | Indicators |
|---|---|
|
Investigation: Investigation of novel influenza cases |
This interval is indicated by the identification of an animal case of influenza A subtype with potential implications for human health or identification of a human case of novel influenza A anywhere in the world. |
|
Recognition: Recognition of potential for ongoing transmission |
This interval is indicated by an increasing number of cases or clusters of novel influenza A in humans and by virus characteristics indicating potential for ongoing human-to-human transmission anywhere in the world. |
|
Initiation: Initiation of the pandemic wave |
This interval is indicated by confirmation of cases of novel influenza A in humans and demonstration of efficient and sustained human-to-human transmission anywhere in the world. |
|
Acceleration: Acceleration of the pandemic wave |
This interval is indicated by an increasing rate of novel influenza A cases identified nationally, indicating establishment in the country. |
|
Deceleration: Deceleration of the pandemic wave |
This interval is indicated by decreasing rates of novel influenza A infection. |
| Preparation: Preparation for a future pandemic wave | This interval is indicated by sporadic cases of novel influenza A infection and surveillance rates returning to baseline. |
Source: Holloway R, Rasmussen SA, Zaza S, Cox NJ, Jernigan DB; Influenza Pandemic Framework Workgroup. Updated preparedness and response framework for influenza pandemics. MMWR Recomm Rep 2014;63(No. RR-6).