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Friday, November 19, 2010

Flu Shots and Magical Thinking

No, this is not me...  (my hair isn't that gray)
Around 1976, when Gerald Ford was president, I was at the University of Wisconsin, Madison.

Word came down from the press that we were all going to die of the Swine Flu so we had better all line up for our free vaccination.  I was away at my first year of college.  I remember being the student union and seeing a long line of folks lined up for their free flu shot that would save their lives.

To this day I can still see the line.  It was long, it was slow moving.  It reminded me of cattle lining up for slaughter.  And, as it turned out my chances of harm from Swine Flu versus the flu shot itself were far less, zero in fact, because the only person to die in 1976 of Swine Flu was 19-year-old Pvt. David Lewis of Ashley Falls, Mass.

Each year my mother calls me and worries about getting a flu shot.

"What should I do" she asks.

We always talk about it though she always makes up her own mind.

"I'm not going to get it..." she tells me.  She sees the long lines, the same as I saw 35 years ago, at the local drug store or in the lobby of the building where she lives.  I think it scares her.

So what's the deal with flu anyway?  Like 1976, 2009 was the year that H1N1 was going to wipe humanity off the face of the earth, just like the 1918 flu pandemic.

But is it true?

The first thing I did was track down the CDC (here in the US) and try to figure out what the hell it is that they do to track flu.  The best I could come up with is this website:  Its sort of like a death-star command bridge of CDC flu data collection.

Its very interesting.  They divide the year up into 52 weeks and publish a kind of run-on chart that shows types of flues and reports about numbers of cases.  The most interesting char off the top was this one:

The basic idea here is this.  The top black line is the "epidemic threshold".  If the red line, representing the percent of all deaths due to pneumonia and influenza, crosses over the top black line one presumes there in an epidemic.  The bottom black line is the baseline of flu deaths.

So around you see a big spike around the 10th week of 2008 - presumably a big epidemic - at least according to the chart.

Hold on... 2008?  I don't recall anything about that.  Do you?

Sure there was SARS - a dud - and that was 2005.  Then there was H1N1 - but that was late 2009 (which you can see as a bump around the end of 2009).

Some Googling yields the CDC's report on the 2007-2008 flu season through May, 2008.  It can be found here

My, my.  There is some interesting data here, er, well, the lack of data.  No discussion of the epidemic listed on the chart.  Nothing.  There is some discussion on how all this flu stuff is not as exact as it might be and there is a discussion of the effectiveness of the vaccine.

Quoted from the link in part: "Interim results from a study carried out this season with the Marshfield Clinic in Wisconsin found overall vaccine effectiveness (VE) of 44% for the 2007-08 flu shot. This included VE of 58% effectiveness against the predominant influenza A (H3N2) viruses, but no effectiveness against influenza B viruses. No influenza A (H1N1) viruses were seen in the study population, so VE against these viruses could not be assessed. A higher VE against H3N2 viruses than against influenza B viruses was likely because the circulating H3N2 strains and H3N2 strain in the vaccine were closely related while the circulating B viruses were antigenically and genetically much different from the influenza B virus in the vaccine and there was little to no cross-reactivity. "

Seems like the data and charts don't match the conclusions here.

Now, I'm a reasonably smart guy.  This stuff is a jumble of nonsense.  None of it matches.  And, of particular interest here, it seems like each year all the prior years web pages on results are replaced by the next years results, i.e., there is no year-to-year comparison of what's going on.

So an effectiveness rate of 44%, eh - whatever that means, and attempting to find this calculation on the CDC so far has left me empty handed.  After some surfing I came up with this site.

This paints a somewhat (or, perhaps significantly) troubling picture of the macro case of "vaccine effectiveness".   Results seem to range from cutting influenza-like symptoms 35% to a 50% reduction in all-cause mortality for the elderly to another study that "found no link between flu vaccination and a reduced risk of this illness."  The author of the first study, not surprisingly, was none other than the CDC.

A bit later in this same article we learn that "Influenza only causes 5% of winter deaths at most" so a flue shot is unlikely to produce a 50% reduction in all-cause mortality.  Further it claims that, for the elderly, a true epidemiological study would be unethical for various reasons (I wonder if its as unethical as sending them out to get a vaccine with, at best, a dubious benefit).

And finally, there's this comment "The seniors who are healthy and are able to go get a flu shot are less likely to get pneumonia or die. The benefits [of the influenza vaccine] are probably real but rather small..."

Seems to me that at best the effectiveness rate for this vaccine is about that of a placebo, at least for elderly patients.  If you haven't heard of it the placebo effect is what happens when you give someone a pill and tell them the pill does something even though the pill is actually just a dummy.  It turns out that in many cases up to about one third of the people experience the effect they were told about - even though the pill does nothing. 

So effectively is the shot, at least for the elderly, just a placebo...?

(I am not so sure magical thinking, at least in the context of one's health, is not so far off the placebo effect.)

On the other hand, people experience real vaccine side effects - they are well documented.  Any my mother is right to fear them.

So which is more dangerous?

A vaccine of dubious effectiveness or doing nothing at all?

Mother still apparently knows best...

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