What do the WHO pandemic alert phase changes mean to you?

(CIDRAP Business Source Osterholm Briefing) – Big news today: The World Health Organization (WHO) ended days of speculation and finally bumped the pandemic alert level to phase 4. What's more, it did so after releasing revamped definitions and meanings yesterday.

Your head may be spinning at the moment, so let's take a deep breath and make sense of all the news today. As you may recall, the first pandemic phase alerts were released in 1999, then revised in 2005. A draft of the current changes was released last October.

How have the phases changed?

The WHO describes six phases and has added a "post peak period" and a "post pandemic period." The way they're grouped and the descriptions of each phase have changed. According to the WHO's guidance on how to use the new phases, the revisions make them "easier to understand, more precise, and based on observable phenomena."

The five new groupings of phases are the following:

  1. Predominantly animal infections; few human infections (phases 1-3)
  2. Sustained human-to-human transmission (phase 4)
  3. Widespread human infection (phases 5-6/pandemic)
  4. Possibility of recurrent events (post peak)
  5. Disease activity at seasonal levels (post pandemic)

Here's how the old (2005) and the new (2009) versions compare:

Phase 1

Old: Low risk of human cases

New: No animal influenza virus circulating among animals have been reported to cause infection in humans

What's changed: More specificity

Phase 2

Old: Higher risk of human cases; considered a "new virus in animals, no human cases" phase

New: An animal influenza virus circulating in domesticated or wild animals is known to have caused infection in humans and is therefore considered a specific potential pandemic threat

What's changed: More specificity

Phase 3

Old: No or very limited human-to-human transmission (considered a "pandemic alert" phase)

New: Animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks; considered a phase described as "predominantly animal infection; few human infections"

What's changed: A "pandemic alert" phase has been removed.

Phase 4

Old: Evidence of increased human-to-human transmission

New: Human-to-human transmission of an animal or human-animal influenza reassortant virus able to sustain community-level outbreaks has been verified

What's changed: We now have a benchmark by which we can determine what increased human-to-human transmission actually means. There must be sustained outbreaks in the community.

Phase 5

Old: Evidence of significant human-to-human transmission

New: The same identified virus has caused sustained community-level outbreaks in two or more countries in one WHO region

What's changed: Now it is necessary to have the level of infections that is currently occurring in Mexico (ie, found in two or more countries). This gives another benchmark that is much more specific than what was found in the old definition.

Phase 6

Old: Efficient and sustained human-to-human transmission

New: In addition to the criteria defined in phase 5, the same virus has caused sustained community-level outbreaks in at least one other country in another WHO region

What's changed: Not much. The pandemic is well under way.

New: Post peak period

Levels of pandemic influenza in most countries with adequate surveillance have dropped below peak levels.

New: Post pandemic level

Levels of influenza activity have returned to the levels seen for seasonal influenza in most countries with adequate surveillance.

What do the changes mean to you?

I'll be brief here. Before the update, phase 4 put us on high alert and gave us time to activate our plans—if we had them. The new phase 4, which requires significant human-to-human transmission at the community level, means the stakes are much higher when we reach this point. And if we haven't planned, we have to scramble. Preparation per se is a thing of the past.

So what should you do now that phase has been elevated?

So much remains uncertain about this new virus. But as we mentioned in the last Special Edition of Osterholm Briefing, it's time to activate your plan. And if you don't have a plan, again I'll refer you to the list of seven actions (question 4) mentioned in that column. It's not too late to do something, including notifying senior management how urgent the need is now.

At the same time, I cannot emphasize enough how important it is to realize that this outbreak could go any number of ways. It could turn into a full-blown pandemic any day now. It could disappear soon, only to reappear later. Or it could fizzle altogether. We just don't know, and it's important to communicate that point frankly. It's also important to never forget that if this new H1N1 swine flu virus doesn't cause the next pandemic, another influenza virus some day will do so.

And what about traveling?

There's been considerable confusion about the difference between "containment" and "transmission." Here's the straight story. The swine flu outbreak cannot be contained; it has already leaked out of Mexico to the rest of the world. The possibilities for containment are long gone. However, we can take actions to reduce the transmission of the virus between people. Take a look at the resources posted in the Employee Protection section of the Source Web site for a full range of options.

As for traveling, the WHO as I write this has not advised restrictions on regular travel or the closure of borders. The CDC, however, just recommended that US travelers avoid all nonessential travel to Mexico out of concern that travel to Mexico "presents a serious risk for further outbreaks of swine flu in the United States." The CDC is also recommending that travelers stay informed, follow local public health guidelines including any movement restrictions and prevention recommendations, and be aware that Mexico is checking all exiting airline passengers for signs of swine flu. Such exit screenings may cause significant delays at airports. In the travel advisory, CDC also makes recommendations regarding antiviral medications. I encourage you to review these. Few if any pandemic exercises or drills have occurred without such actions being envisioned. If you want to cut down on nonessential travel to places besides Mexico, this seems appropriate at this time.

Bottom line for business

These new phases are meant to help direct the governments of the world with regard to public health action, allocation of resources, and as a measure of disease level. And they clearly give the private sector more understandable trigger points for implementing preparedness plans. We consider them zones for preparedness that ensure a certain level of safety. In other words, simply because it took years to move from the old phase 3 to new phase 4, we can't expect it will take as many or more years before we see another phase change.

It might take only days to move to the next phase. Stay tuned.

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