Thursday, October 29, 2009

Why Swine Flu is not a bunch of hogwash

This updates my previous blog: "Why Swine flu is a bunch of hogwash?"

Things have changed a bit in the months since that blog, and the hysteria I cited has leveled off. President Obama did declare a swine flu emergency a couple days ago, but I think that was a good idea.

Here is what has changed:
1) Swine flu deaths have been at epidemic levels the last three weeks. The chart below (from the CDC) shows flu and pneumonia deaths as a percentage of all deaths. The upper black line indicates epidemic level, and the red line is the current level. The graph shows four years of weekly figures.While this graph doesn't look too serious, and 2008 levels were much further above the threshold at their peak, the scary thing here is that it is so early in the season. This graph serves as a reminder, too, that every year the flu kills thousands of people, and the flu vaccine could prevent a large number of those deaths.

2) Hospitals are already getting crowded. One of the big problems with a real epidemic is the overcrowding of hospitals. This means that the really sick people cannot get treatment, and that is part of the reason the emergency was declared. See this article in USA Today about over-crowding. ok, so it's USA Today, a paper that loves hyperbole, but, again, it's early in the season and any indication of overcrowding at this point is scary.

3) The vaccine is not yet fully available. The regular flu vaccine has been out for weeks. Unfortunately, almost none of the flu this year seems to be covered by that vaccine. The majority seems to be 2009 H1N1 (the swine flu). See this chart for a breakdown. Note the orange/brown is 2009 H1N1, and note the yellow means it is not tested for sub-type, so almost all typed flu is swine flu.
That's why I am worried. The other concern is that, even when the vaccine does come out, people won't take it. See my brother's blog about why you should and the crazies who say you should not.

1 comment:

Anonymous said...

following the link to CDC ... yes, that was the start of a high P+I mortality wave.
{Ooops, what is happening right now ? Americans stop dying . This seems to be the
(winter) season with fewest deaths since long}.
And that although H3N2 was dominating which is usually associated with more deaths.
But the ILI level was low over the whole season. (same link)
Now back to 2009, In August PCAST made their estimate of 30000-90000 deaths in USA.
and upto 1.8M hospital admissions :
What came were ~12500 deaths and 275000 admissions.
Much fewer deaths than the average ~35000 flu deaths per season.
H1N1 usually causes fewer deaths and so did swine flu.
But it attacked the younger and so the number of years of lives lost
was as big as in other seasons.
Now, what was wrong with the forecast for the president ? Just a few weeks later
Lipsich gave an interview saying the numbers were probably too high.
We saw the New York - wave in June,July with many infections but few deaths.
This was a full flu-wave, what we could expect in the winter. Unless the disease
changes, of course, as it did in 1918.
Then in August it became already clear that Australia also had few deaths.
But the forecast wasn't officially corrected. Why ?