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<\/a><\/span>There are two separate issues here. On one hand, we have the accumulation and verification of case by case data, and on the other hand, we have the spread of the flu. Over time, the quality of the data will become good enough to make longer term projections and to make assumptions about the missing or lower quality data areas of the world. So, right now, as we see reports of more states in the US or more countries across the world reporting cases for the first time, are we watching the actual spread of the flu, or the improvement of data? Answer: Both, and we can’t separate the two right now with any degree of reliability.<\/p>\n5) Regarding the flu’s virulence and mortality: Good news and bad news. I have one piece of good news and two pieces of bad news.<\/p>\n
First the good news: It does seem (see above) that this flu is not extra deadly.<\/p>\n
Now the first bit of bad news: The seasonal flu is deadly. This new flu … the swine flu … is like the seasonal flu. It is also deadly. It might be that the currently spreading strain of Swine H1N1 ends up being less deadly, it might end up being more deadly, but if it turns out to be about the same as the seasonal flu and goes though a similar cycle, you can expect several tens of thousands of Americans to die of it.<\/p>\n
Maybe thats a good thing. Maybe killing 38,000 Americans twice in one year instead of once will result in a change in attitude towards both the flu and towards vaccination in general. Maybe I’m too cynical. Maybe I’m not.<\/p>\n
Now the second piece of bad news, and this is the scary bit. This flu may be worse than a regular flu in that more people will get it … there is not vaccine available now, so it’s initial spread will be unchecked compared to a normal seasonal flu for which vaccines may have been distributed. There is probably not as much of an immunity to this flu as for the seasonal flu (this has yet to be determined but is likely true) so it may be that more people will end up getting this flu.<\/p>\n
Fine. But that’s not the real bad news.<\/p>\n
The real bad news is that since this is a new flu part of which (flu has different parts that may have different histories) only recently entered the human environment, there might be a slightly higher than we would like to have chance that this flu, while it swaggers around the human population making people sick, will recombine with one or more other flu viruses that are already out there with very nasty results.<\/p>\n
This flu could spread around the world as a regular flu, making lots of people sick but not being overly deadly. Then, some time during its spread, or even after it has largely abated, it could mutate through recombination (of some of its parts) and come back as a much more severe flu, causing a truly deadly world wide pandemic.<\/p>\n
How possible is this? We have no way of knowing, but that scenario has happened before. From a paper by Taubenberger and Morens:<\/p>\n
\nHistorical records since the 16th century suggest that new influenza pandemics may appear at any time of year, not necessarily in the familiar annual winter patterns of interpandemic years…. Thereafter, confronted by the selection pressures of population immunity, these pandemic viruses begin to drift genetically and eventually settle into a pattern of annual epidemic recurrences caused by the drifted virus variants.<\/p>\n
In the 1918-1919 pandemic, a first or spring wave began in March 1918 and spread unevenly through the United States, Europe, and possibly Asia over the next 6 months … Illness rates were high, but death rates in most locales were not appreciably above normal<\/em>. A second or fall wave spread globally from September to November 1918 and was highly fatal<\/em>. In many nations, a third wave occurred in early 1919 … Clinical similarities led contemporary observers to conclude initially that they were observing the same disease in the successive waves. The milder forms of illness in all 3 waves were identical and typical of influenza seen in the 1889 pandemic and in prior interpandemic years. In retrospect, even the rapid progressions from uncomplicated influenza infections to fatal pneumonia, a hallmark of the 1918-1919 fall and winter waves, had been noted in the relatively few severe spring wave cases. The differences between the waves thus seemed to be primarily in the much higher frequency of complicated, severe, and fatal cases in the last 2 waves.<\/p><\/blockquote>\n
That paper characterized the pattern of the 1918 flu well, but was written before some key findings in the nature of flu evolution, so I won’t pass on the speculations those authors provide for why this pattern developed.<\/p>\n
Taubenberger, Jeffery, & Morens, David (2006). 1918 Influenza: the Mother of All Pandemics Emerging Infectious Diseases, 12<\/span> (1)<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"
I have a handful of comments, mostly about how what you are seeing on the news is unimportant, and one comment about why you actually should worry. Within reason. The new Swine Flu has now been verified in nineteen US states, with 141 cases. Technically there is 1 death, but since the young girl who … Continue reading The new swine flu: don’t panic, but there is a very bad WCS<\/span>