Geoscience Reference
In-Depth Information
level tool,
9
and the U.S. Federal Government's [Department of Health and Human
Safety (HHS)] response stage tool.
10
Figure 17.3 depicts these tools.
For each WHO phase or HHS stage, there are “triggers” that lead either organiza-
tion to elevate the levels. These same triggers inform communities and populations
about changes in the pandemic's nature. As Figure 17.3 illustrates, WHO and HHS
monitor these triggers, but lower level entities, including state and regional public
health organizations, local community health authorities, and even businesses, also
should monitor the triggers. The more aware these organizations are, the more pre-
pared they will be to implement appropriate preparedness actions.
WHO Phases
Federal Government Response Stages
Interpandemic period
No new influenza virus subtypes have been
detected in humans. An influenza virus subtype
that has caused human infection may be present
in animals. If present in animals, the risk of
human disease is considered to be low.
1
New domestic animal outbreak
in at-risk country
0
No new influenza virus subtypes have been
detected in humans. However, a circulating
animal influenza virus subtype poses a substantial
risk of human disease.
2
Pandemic alert period
New domestic animal outbreak
in at-risk country
0
Human infection(s) with a new subtype, but
no human-to-human spread, or at most rare
instances of spread to a close contact.
3
1
Suspected human outbreak overseas
Small cluster(s) with limited human-to-human
transmission but spread is highly localized,
suggesting that the virus is not well adapted
to humans.
Larger cluster(s) but human-to-human spread still
localized, suggesting that the virus is becoming
increasingly better adapted to humans, but
may not yet be fully transmissible (substantial
pandemic risk).
4
2
Confirmed human outbreak overseas
5
Pandemic period
Widespread human outbreaks in
multiple locations overseas
3
4
First human case in North America
Pandemic phase: increased and sustained
transmission in general population.
6
5
Spread throughout United States
Recovery and preparation for
subsequent waves
6
Figure 17.3
WHO and federal pandemic response levels. (From U.S. Department of
Health and Human Services, www.PandemicFlu.gov, 2009.)
