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CBS Investigation: Swine Flu Cases Overestimated?

 


# 3864

 

 

Today CBS Investigative reports has a report about how the vast majority of people who have had influenza-like-illnesses over the summer probably didn’t have the H1n1 virus.

 

If this sounds a tad familiar, well all I can do is point to a blog I wrote nearly 2-weeks ago, called ILI’s Aren’t Always The Flu.

 

 

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Although nearly all of the influenza circulating in the the US and Canada right now is apparently the novel H1N1 `swine’ flu, it would be incorrect to say that if you have a flu-like illness, you must have the pandemic flu.

 

Last week’s numbers from the CDC’s FluView, which I’ve plugged into the above spreadsheet so as to generate a graph, show that more than 72% – almost 3/4ths – of all virus samples tested from people who had flu-like symptoms came back negative for influenza.

 

 

The CBS report, however, goes quite a bit beyond what I covered in my blog, although it raises the same central issue.  

 

That many people who think they’ve already had the H1N1 virus, may have had some other respiratory ailment.

 

This investigative report, however, seems to make a big deal over the CDC’s decision to halt individual testing for the H1N1 virus over the summer. 

 

While – in a perfect world – I’d prefer to see every suspected influenza-like-illness tested with state of the art PCR testing, that simply isn’t practical.  

 

State & CDC labs were overwhelmed very early in this outbreak with demands for testing, and could never have hoped to keep up.  Which is why I find far less to criticize about the CDC’s decision on reduced testing than does this investigative report.

 

The testing, by the way, even at State labs, isn’t 100% accurate.   Samples degrade, or may have been taken or shipped improperly, or may simply have been taken at the wrong time from patients when viral shedding was low.  

 

Unlike the CDC labs, which get samples from sentinel doctors and clinics used to taking and shipping swabs, state labs were getting samples from `over-the-transom’ from doctors from just about everywhere. 

 

I would expect a lower percentage of positive tests, just based on those factors alone.  So my level of comfort with the numbers we have, particularly early in the outbreak, is less than supreme. 

 

I’ve no doubt that millions of Americans have been infected by the H1N1 virus over the summer.  How many, of course, is unknown.

 

But I also suspect that a good many only think they were infected with H1N1.  That they suffered some other ILI, and may have unwarranted hope that they are now immune.

 

The CBS report makes for interesting reading.  And it shows gaps in the flow of information from the states, to the CDC, and on to the press.   A frustration, I’m sure, to the news agencies trying to cover this story.

 

 

 

Swine Flu Cases Overestimated?

 

(CBS) If you've been diagnosed "probable" or "presumed" 2009 H1N1 or "swine flu" in recent months, you may be surprised to know this: odds are you didn’t have H1N1 flu.

 

In fact, you probably didn’t have flu at all. That's according to state-by-state test results obtained in a three-month-long CBS News investigation.

 

The ramifications of this finding are important. According to the Center for Disease Control, CDC, and Britain's National Health Service, once you have H1N1 flu, you're immune from future outbreaks of the same virus. Those who think they've had H1N1 flu -- but haven't -- might mistakenly presume they're immune. As a result, they might skip taking a vaccine that could help them, and expose themselves to others with H1N1 flu under the mistaken belief they won't catch it. Parents might not keep sick children home from school, mistakenly believing they've already had H1N1 flu.

 

(Continue . . .)

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