"... Even those figures pale in comparison with the 1918-19 flu pandemic: At least
550,000 people died in the United States alone. The worldwide death toll was estimated at 20 million to 40 million, or perhaps even as many as 100 million by some accounts. The
flu killed more people than World War I (which may have contributed to its spread).
....
So does that mean the current outbreak is just a piddling pandemic? Not necessarily.
For one thing, it's far too early to assess how this outbreak will end up. For another thing, the pattern of the deaths so far is distressing. Both those caveats draw on the lessons learned from the 1918 flu.
The age factor
"The big difference between seasonal flu and pandemic flu is that when you move to pandemic flu, you get a pattern that the older people are not affected," said Lone Simonsen, an epidemiologist at George Washington University who is also the founder and president of SAGE Analytica. The age distribution curve for a typical seasonal flu looks like a "U," while the distribution pattern for the
1918 flu was more of a "W," as seen on this chart.
Experts worry that the
distribution pattern for the current outbreak looks similar. Every death from the flu is a tragedy, but it's particularly tragic when a significant number of the fatalities come in the 20-to-50 age bracket rather than the over-85 bracket.
....
Wave of the future
Even if the current outbreak turns out to be relatively mild, that's not necessarily the end of the story. "When you look at the past pandemics, you observe that they often come in waves," Simonsen said.
She said a review of the records from 1918 show that the year's
first flu flare-up actually came in the spring and summer of that year, in the form of a less lethal but highly transmissible infection. That appears to have been
the precursor for the deadlier waves of influenza that swept across the world that fall.
If the current outbreak turns out to follow a similar pattern, that would be
"good and bad news," Simonsen said. It's bad news because a worse outbreak could conceivably follow. But it's good news, she said, because we'd have "more time to defend ourselves," using all the defenses that have been developed since 1918
....."
http://cosmiclog.msnbc.msn.com/archive/2009/04/30/1917163.aspx