The Six Phases of Pandemic Alert

Posted on May 27, 2006

The cluster of bird flu deaths in a single family in Indonesia has raised concerns that WHO might raise the pandemic alert level for H5N1 from Phase 3 to Phase 4. Here are the six phases of Pandemic Alert according to a Reuters AlertNet article.
Inter-pandemic phase -- Low risk of human cases.

New virus in animals, but no human cases -- Higher risk of human cases

Pandemic Alert -- No or very limited human-to-human transmission

Clusters of human cases suggesting increased adaptability of the virus -- Evidence of increased human-to-human transmission

Larger clusters of human cases over longer periods -- Evidence of significant human-to-human transmission

Pandemic -- Efficient and sustained human-to-human transmission
The AP says WHO will not raise the bird flu status to phase 4 despite the growing cluster in Indonesia.
Also today, the WHO reiterated that it will not raise its global pandemic alert level from phase 3 (human infection, but no or only rare human-to-human spread) to phase 4 (small clusters with limited human-to-human transmission, but spread is highly localized). The agency said this week that human-to-human-to-human (two-generation) transmission might have occurred in the North Sumatra cluster. But officials have observed no further spread beyond the family cluster and no ominous mutations in H5N1 viruses that have been analyzed.

Paul Gully, senior adviser to WHO's top avian flu official, Margaret Chan, said in a third Reuters report, "Our feeling now is there is nothing new that has happened which would make us want to consider moving to level 4."
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