Call this part 2 on swine flu Learning from History.
Consider the 1918 Influenza Pandemic.
That flu is worth considering as a predictive model for the path of 2009 H1N1 for two reasons:
(1) Unlike most influenza, its main victims were the young.
(2) It caused death through its attack on the lungs.
A third reason is discussed below.
The new H1N1 influenza virus bears a disturbing resemblance to the virus strain that caused the 1918 flu pandemic, with a greater ability to infect the lungs than common seasonal flu viruses, researchers reported on Monday.
Tests in several animals confirmed other studies that have shown the new swine flu strain can spread beyond the upper respiratory tract to go deep into the lungs -- making it more likely to cause pneumonia, the international team said.
In addition, they found that people who survived the 1918 pandemic seem to have extra immune protection against the virus, again confirming the work of other researchers.
We have more ways to combat disease now - thanks to pure and applied science - but it is still worth reminding ourselves of the seriousness of the 1918 pandemic. link
The effect of the [1918] influenza epidemic was so severe that the average life span in the US was depressed by 10 years. The influenza virus had a profound virulence, with a mortality rate at 2.5% compared to the previous influenza epidemics, which were less than 0.1%. The death rate for 15 to 34-year-olds of influenza and pneumonia were 20 times higher in 1918 than in previous years (Taubenberger). . . . One physician writes that patients with seemingly ordinary influenza would rapidly "develop the most viscous type of pneumonia that has ever been seen" and later when cyanosis appeared in the patients, "it is simply a struggle for air until they suffocate," (Grist, 1979). Another physician recalls that the influenza patients "died struggling to clear their airways of a blood-tinged froth that sometimes gushed from their nose and mouth," (Starr, 1976). The physicians of the time were helpless against this powerful agent of influenza.
. . .
In the two years that this scourge ravaged the earth, a fifth of the world's population was infected. The flu was most deadly for people ages 20 to 40. This pattern of morbidity was unusual for influenza which is usually a killer of the elderly and young children. It infected 28% of all Americans (Tice). An estimated 675,000 Americans died of influenza during the pandemic, ten times as many as in the world war.More on the 1918 pandemic here from PBS, paid for with your tax dollars and contributions and underwriters.
Another similarity to the 1918 pandemic is currently missing - bird flu. Research reviewed by the Centers for Disease Control (CDC) explains:
the 1918 virus appears to be an avianlike influenza virus derived in toto from an unknown source, as its 8 genome segments are substantially different from contemporary avian influenza genes. Influenza virus gene sequences from a number of fixed specimens of wild birds collected circa 1918 show little difference from avian viruses isolated today, indicating that avian viruses likely undergo little antigenic change in their natural hosts even over long periods.
If we get that missing part of the currently circulating virus, then we will have far more to worry about.
One piece of good news is that ongoing research shows flu vaccination and infection have provided long lasting immunity and partial immunity. This is one reason the 1918 flu had such a strong impact on the young versus the old (reversing the normal demographic effect of flu). Those varying levels of immunity may provide protection from the worst ravages of the disease. They may also help limit the number of people who can be disease vectors.
But, as the CDC study says, there is missing information, and much more research is needed.
One theory that may partially explain these findings is that the 1918 virus had an intrinsically high virulence, tempered only in those patients who had been born before 1889, e.g., because of exposure to a then-circulating virus capable of providing partial immunoprotection against the 1918 virus strain only in persons old enough (>35 years) to have been infected during that prior era. But this theory would present an additional paradox: an obscure precursor virus that left no detectable trace today would have had to have appeared and disappeared before 1889 and then reappeared more than 3 decades later.
Epidemiologic data on rates of clinical influenza by age, collected between 1900 and 1918, provide good evidence for the emergence of an antigenically novel influenza virus in 1918. Jordan showed that from 1900 to 1917, the 5- to 15-year age group accounted for 11% of total influenza cases, while the >65-year age group accounted for 6% of influenza cases. But in 1918, cases in the 5- to 15-year-old group jumped to 25% of influenza cases (compatible with exposure to an antigenically novel virus strain), while the >65 age group only accounted for 0.6% of the influenza cases, findings consistent with previously acquired protective immunity caused by an identical or closely related viral protein to which older persons had once been exposed. Mortality data are in accord. In 1918, persons >75 years had lower influenza and pneumonia case-fatality rates than they had during the prepandemic period of 1911–1917. At the other end of the age spectrum, a high proportion of deaths in infancy and early childhood in 1918 mimics the age pattern, if not the mortality rate, of other influenza pandemics.
By the way, the CDC is a government agency, so their work and reports ARE available free. Your tax dollars paid for them. Just be grateful some ignorant zealot did not zero the research out.
One more thing we can learn is that the more we get piggy about funding, the less likely are we to be equipped to be safe and healthy. And the less will be our national security.
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