'It's Over': WHO calls H1N1 'post-pandemic'--what does that mean to you?

'History is the version of past events that people have decided to agree upon.'

—Napoleon Bonaparte

(CIDRAP Business Source Osterholm Briefing) – This week brought another milestone to the human-influenza history book. The World Health Organization (WHO) on Tuesday declared that the novel H1N1 influenza pandemic is over, that it has "largely run its course." The WHO Emergency Committee, the expert advisory group that advises WHO on the pandemic status of influenza, concluded that (1) virus behavior and human illness occurrence in the Southern Hemisphere, now experiencing winter, as well as (2) the relative lack of current human influenza illness activity in the Northern Hemisphere warrant the downgraded status. The 2009 H1N1 influenza pandemic is now in a "post-pandemic" phase.

With this milestone moment, it's worth taking a quick glance into the windshield as well as the rearview mirrors of this pandemic. This glance may help answer some questions others are asking about "what really happened" and "what can we expect" in the coming months.

Looking through the windshield

Even with the welcomed announcement on Tuesday, WHO Director-General Dr. Margaret Chan cautioned that the novel H1N1 virus warrants close monitoring and still poses a real danger to young people, pregnant women, and others with chronic health conditions. Dr. Chan's caution should be taken seriously for several reasons:

  • H1N1 is active in New Zealand. While new cases of H1N1 illness in the Southern Hemisphere are not occurring at a "widespread, pandemic level" (my words), on Wednesday the New Zealand National Influenza Centre announced that reported influenza activity in that country jumped 86% from the previous week and now exceeds the 2008 winter peak of illness seen with the H3N2 and the previous H1N1 strains.
  • Similar reports are coming out of Thailand and India. As was seen during most of the novel H1N1 pandemic, many of the most serious cases of illness are occurring in the groups cited above by Dr. Chan as representing a serious threat.
  • Plenty of people don't have immunity yet. The current flu experience of the Southern Hemisphere is "a shot across the bow" to Northern Hemisphere countries as we prepare for our upcoming 2010-11 flu season. Recent studies have determined that about 30% to 40% of people were actually infected with the novel H1N1 virus over the past 16 months in North America and Europe. These results, taken together with the estimated number of people vaccinated over the past 10 months, mean that 40% to 50% of the population in North America and Europe (particularly people under 65 years of age) remain susceptible to H1N1 infection. The number of susceptible people in most other countries, where very limited vaccination occurred, is even higher.

What can you do? The bottom line message for you and your organization is to continue to push hard to get your employees and colleagues vaccinated. The seasonal influenza vaccine available in the United States for the upcoming season contains both seasonal strains of H3N2 and influenza B, as well as the novel H1N1 pandemic strain.

Glancing in the rear-view mirrors

No one needs to remind you that for every legitimate pandemic preparedness expert who stuck her or his neck out to predict and prepare us for what we've just experienced, there are numerous arm-chair quarterbacks who will declare why their "after-the-fact" assessment makes them the real experts. I just read an editorial from such an "expert" this morning. It was published as an Op-Ed piece in a Canadian paper and explained that the H1N1 pandemic was really "not much out of the ordinary."

We can expect that the drumbeat of such critics will continue and likely get louder as time goes on. That puts you in a tough spot, maybe even the hot seat again. So be sure you know the facts: This pandemic was a very real event that caused extraordinary pain and suffering—and lots of very early deaths. No, the total number of deaths did not exceed that of previous pandemics or even a bad seasonal flu year. But the toll on the years of productive life lost was extraordinary and shows the undeniably serious nature of the 2009 H1N1 influenza. I explained the concept of Years of Life Lost (YLL) first in my Dec 14, 2009, column and again in my Mar 25, 2010 column. The median age of death from the H1N1 pandemic was the early 40s, whereas with seasonal flu and the 1957 and 1968 pandemics, they were the 60s to early 70s.

Now, take a look at this graphic representation comparing past pandemics and seasonal influenza in terms of total number of deaths and YLL. See how the 2009 H1N1 influenza pandemic stacks up.

Use this information anytime your efforts to prepare your organization are scrutinized. In no way was this pandemic a "non-event."

What about H5N1?

One of the more frustrating things about the WHO announcement this week was the lack of information or clarity about the H5N1 ("avian" flu) virus that is still killing people in Asia and Africa. It's the virus that launched global pandemic preparedness efforts—and it hasn't gone away. Nothing has materially changed about the H5N1 virus. Like it or not, we still have to consider it a threat. So are you prepared for the possibility that H5N1 (or some other virus) could launch another pandemic tomorrow or even 2 years from now?

If leaders in your organization think that having been through the H1N1 pandemic is reason to let down your guard, they need to understand the random nature of events. Take the floods in Iowa, for example. For the 3rd time in 4 years, the state is experiencing devastating floods that are expected once in 500 years. All bets are off when it comes to random events.

Bottom line for organizations

Don't let your organization drop its guard because the WHO says H1N1 has entered a post-pandemic phase. Even the WHO isn't letting its guard down. Here are the main points to remember:

  1. The 2009 H1N1 influenza pandemic was real and it did plenty of damage, particularly when it comes to years of life lost.
  2. The virus responsible for the first influenza pandemic of the 21st century isn't going away; enough people lack immunity so that your organization could still be affected during the coming flu season.
  3. Keep your eyes on H5N1 and remember that it (or some other novel influenza virus) could surprise us at any time. Be ready and stay ready.

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