Mild Pandemic? Bite Your Tongue

[indigo girl]

For those unfamiliar with him, Dr. Osterholm is director of the Center for Infectious Disease Research and Policy (CIDRAP), director of the NIH-supported Minnesota

Center of Excellence for Influenza Research and Surveillance (MCEIRS) within

CIDRAP, a professor in the Division of Environmental Health Sciences, and an

adjunct professor in the Medical School, University of Minnesota. He is also a

member of the Institute of Medicine (IOM) of the National Academy of Sciences.

I had the great pleasure of attending his last seminar on preparing business

for the H1N1 pandemic. I read his recent column being discussed by the public

health officers at Effect Measure. Osterholm did a great job of explaining the

difference between this pandemic and the three preceding it. Better yet, he

discusses the senselessness of comparing novel H1N1 to seasonal flu which

is something that many keep trying to do for some strange reason. It is true

that it is somewhat like comparing apples to oranges.

One of the interesting things that he had to say about the 1957 and 1968

pandemics that I was unaware of, is that many of the deaths in those two

events occurred in the elderly population. That is not what is happening

now, however with swine flu. He described those outbreaks as being more like

"super seasonal influenzas." Seasonal flu typically targets the elderly, we know

that frequently, the elderly have many pre-existing health issues.

He had two other very interesting things to say about the latest CDC figures from

last week that I was surprised to learn. This novel swine flu has now caused more

cases than seasonal flu. That's right. There have been about 16 milion more cases

than the estimated 31 milion cases of seasonal flu that happen every flu season.

It has also caused more hospitalizations, (213,000) about 13,000 more than

seasonal flu usually does.

Both Osterholm and we find CDC's most recent estimates (November 14) of about 10,000 deaths, 47 million infections and over 200,000 hospitalizations "credible and thoughtful." To compare the oft quoted number of 36,000 excess deaths from seasonal flu to this 10,000 number is an "apples and oranges" affair. The 36,000 number is an excess mortality figure derived by different and non-comparable methods (see our post here for more details). Here is some of Osterholm's version:

In that CDC study, only 9,000 of those estimated annual seasonal deaths are due directly to influenza or secondary bacterial pneumonia. The other deaths are among persons who have influenza and who die of events like heart attacks or strokes. If you want a comparison, think of the guy who has a heart attack while snow blowing his driveway after a large snowstorm and whose death is labeled "storm-related."

More important, though, is what we pointed out early on. It's not just the number of deaths but the pattern of illness in the population, flu's descriptive epidemiology:

More than 90% of the estimated seasonal influenza deaths occur in the elderly, who in many instances have existing serious health conditions that mean their deaths may not be far off, regardless of their influenza illness. We all realize that death is inevitable, and, as a public health practitioner, I find that this mad race to eliminate the top 10 causes of death is not always well thought through. If we were to accomplish such a goal, there would be 10 new leading causes of death, and I'm not so sure some of those would be better than the current ones. But I think we can all agree that "early deaths"—or those that occur well before our elderly years —just shouldn't happen. The way we count influenza mortality, an influenza-related death in an 87-year-old person with advanced Alzheimer disease is the same as the death of a 22-year-old otherwise perfectly healthy pregnant woman. Both deaths are equally tragic, but any reasonable person would agree they are not equivalent public health outcomes.

[snip]

Please read the rest of the Revere's commentary over here: http://scienceblogs.com/effectmeasure/2009/12/mild_pandemic_bite_your_tongue.php

The Editors of Effect Measure are senior public health scientists and practitioners. Paul Revere was a member of the first local Board of Health in the United States (Boston, 1799). The Editors sign their posts "Revere" to recognize the public service of a professional forerunner better known for other things.

[itsmejuli]

Its been my experience so far that the overwhelming majority of people coming in to the H1N1 vaccination clinics are >64 yrs.

from the link above

Of the estimated 9,820 deaths:

• 1,090 (11%) have occurred in children 0-17 years of age
  
• 7,450 (76%) in people 18-64 years of age
  
• 1,280 (13%) in people over 65 years of age
  

[indigo girl]

Its been my experience so far that the overwhelming majority of people coming in to the H1N1 vaccination clinics are >64 yrs.

from the link above

That would not surprise me. The elderly really do seem to want the flu vaccines perhaps because they know just how vulnerable they are if they get influenza.

The youngsters, OTOH, don't get that they are being targeted by this virus. No amount of magical thinking about how their immune systems will protect them because they are young and healthy can stand up to the reality of how random some of these deaths are. For the unlucky, it is in fact their very healthy immune systems that will kill them if they develop ARDS and cytokine storm occurs.