April 29, 2009 — Swine flu has pushed the World Health Organization to raise its pandemic alert level to phase 5, which means that a pandemic is imminent.
It’s the second time in a week that the World Health Organization (WHO) has raised its pandemic alert level, which ranges from phase 1 (low risk of a pandemic) to phase 6 (a full-blown pandemic is under way).
“The biggest question is, how severe will the pandemic be?” WHO Director-General Margaret Chan said today in a news conference in Geneva. “We do not have all the answers right now, but we will get them.”
Chan said the swine flu situation is changing rapidly and the swine flu virus is still “poorly understood.”
Chan called on all governments around the world to “immediately activate their pandemic preparedness plan,” noting that each country is free to make its own pandemic plans — and that many countries have been working on pandemic preparedness for years, thanks to concerns about bird flu ( avian flu). “The world is better prepared for an influenza pandemic than at any time in history.”
Earlier today, CDC Acting Director Richard Besser, MD, said that the U.S. is at a “pre-pandemic” level and that it matters less what the situation is called than what’s being done about it, and that the U.S. is taking “aggressive” action to limit swine flu’s impact on human health.
WHO Pandemic Levels
Here is a quick look at the WHO’s pandemic alert phases:
- Phase 1: A virus in animals has caused no known infections in humans.
- Phase 2: An animal flu virus has caused infection in humans.
- Phase 3: Sporadic cases or small clusters of disease occur in humans. Human-to-human transmission, if any, is insufficient to cause community-level outbreaks.
- Phase 4: The risk for a pandemic is greatly increased but not certain. The disease-causing virus is able to cause community-level outbreaks.
- Phase 5: Still not a pandemic, but spread of disease between humans is occurring in more than one country of one WHO region.
- Phase 6: This is the pandemic level. Community-level outbreaks are in at least one additional country in a different WHO region from phase 5. A global pandemic is under way.
Note that all of those phases are about how the virus is (or isn’t) spreading — they’re not about the severity of the disease.