Entries in CIDRAP (2)
Hat-tip to Valerie Mansuy of France for posting this link on Facebook. Mike is a great guy and one of the world's top infectious disease experts. You may recall his hour-long interview with Oprah in 2006 on H5N1 bird flu.
Over at Computerworld, I have just delivered my first blog in over six months! And you thought I blogged slowly over here!
Anyway, I want you to go over there and read it, because I am not supposed to post their blog over here, and vice versa. Here's the link: http://blogs.computerworld.com/15879/dont_write_off_h1n1_pandemic_yet
The CIDRAP study I mention in the blog was authored by Cecile Viboud, a research scientist at the National Institutes of Health's Fogarty International Center, and Lone Simonsen, research professor at the Department of Global Health, George Washington University, School of Public Health and Health Services, Washington, D.C. Another co-author is Michael T. Osterholm, PhD, MPH, director of the University of Minnesota Center for Infectious Disease Research and Policy, and publisher of CIDRAP News. Mike is also a good friend and I am danged glad to know him. I have also mentioned Dr. Viboud's work on this Blogsite, particularly on the 1951 "Liverpool Flu" and her discovery of how deadly that epidemic was in the UK.
The recent CIDRAP study "sought to devise an 'apples to apples' way to compare pandemic and seasonal flu mortality. To estimate the age distribution of pandemic deaths, they relied mainly on a European study of 468 laboratory-confirmed pandemic deaths, published in August 2009. It showed that more than 85% of the deaths were in people younger than 60, with an overall mean age of 37.4, as compared with an estimated mean age of 76 in those who die of seasonal flu. (bold mine)
"The team then developed an estimate of pandemic deaths, given that only a fraction of cases and deaths are laboratory tested and that final statistics will not be available for another 2 to 3 years. This task involved comparing preliminary mortality data from the CDC's 122 Cities mortality surveillance system with final mortality data from the National Center for Health Statistics for 1999 through 2006. The team also used data on deaths in non-flu-season months to estimate the number of monthly deaths that would occur in the absence of flu.
"Using these variables and the 122 Cities data for April through December 2009, the researchers estimated the (US) pandemic death toll to be between 7,500 and 44,100. The lower number is based on deaths classified as due to pneumonia and influenza (P & I). The higher number, Viboud told CIDRAP News by e-mail, is an estimate of "excess all-cause mortality, which is more inclusive as it also takes into account excess deaths from all respiratory and cardiovascular diseases that are associated with influenza infection, but may not be reported as such."
"(Dr. Viboud) added that the 'excess all-cause mortality' approach has traditionally been used to measure the impact of seasonal epidemics and for the 1957 and 1968 pandemics, while the P&I approach has been used in assessing the 1918 pandemic. The team used both approaches to allow fair comparisons with past flu seasons, she said."
The study's results were revelatory.
More than 85% of the H1N1(2009) deaths were in people younger than 60, with an overall mean age of 37.4, as compared with an estimated mean age of 76 in those who die of seasonal flu.
the H1N1 (2009) pandemic, so far, has taken a toll of between 334,000 and 1,973,000 years of life lost (YLL) in the United States.
- The 1968 pandemic, with 86,000 deaths and victims averaging 62.2 years old, caused 1,693,000 Years of Life Lost (YLL).
- The 1957 pandemic, with 150,600 deaths and a mean age of 64.6,caused 2,698,000 YLL.
- The 1918 pandemic, with an estimated 1,272,300 deaths and a mean age of only 27.2, exacted a toll of 63,718,000 YLL.
- An average flu season dominated by influenza A/H3N2-which generally causes more severe epidemics than other strains-causes 47,800 deaths and 594,000 YLL, with a mean age of 75.7. (bold mine)
From the CIDRAP press release:
"Thus, the authors say, the lower end of their YLL estimate for the H1N1 pandemic is comparable to the estimate for an H3N2-dominated flu season, while the upper end is greater than that for the 1968 pandemic. Those impacts, of course, are dwarfed by that of the catastrophic 1918 pandemic.
"Based on US mortality surveillance data, we conclude that the YLL burden of the 2009 pandemic may in fact be as high as for the 1968 pandemic-but that at this time the assessment is still tentative," the report states. More waves of H1N1 cases are likely to come over the next few flu seasons, and later waves could be worse, it says."
Now for the commentary you have come to expect from this Blogsite:
H1N1 is not done infecting people, not by a long shot. And as the CIDRAP study amply demonstrates, the impact of even this "light" pandemic on the future is significant.
Need context? In the US, losing even 300,000 years if life in younger, productive stages will affect future payments to Social Security. Medicare. Federal, state and local taxes. Billions lost. Try factoring that into the budget deficit equations! Not to mention the lost buying power of those persons due to the pandemic.
And of course, it goes without saying that the emotional burden of people having lost youthful loved ones to this disease is tremendous. Watching someone get cut down in the prime of life -- especially someone previously described as healthy -- is a trauma no one would wish on anyone except Osama Bin Laden.
Note something that not even I knew: The 1957 and 1968 pandemics had a much older average age at death than has (so far) the 2009 H1N1 pandemic. No doubt this is because we have the perspective of history and the separation of decades to view the cumulative effects of 1957 and 1968. Since this H1N1 pandemic is far from over, its ultimate average age at death is yet to be determined. But at a shade over 37 years of age, the current age at death is second only to 1918's 27 years in terms of youthful mortality.
I believe it was my buddy John Barry (what a shameless name-dropper I am!) that said in his superior book The Great Influenza, that the average age at death in the United States from 1918-1919 dropped by ten full years as a direct result of both WWI and the 1918 Spanish Flu.
And let us not forget the lingering by-product of 1918's pandemic: Encephalitis Lethargica. That scourge stayed with America (and the world) until it mysteriously dropped from sight around 1930. (Re)Watch "Awakenings" to recall that terrible ordeal.
I also want to crosswalk to a recent study that shows just how antigenically similar the 1918 and 2009 H1N1 viruses are. From Reuters, via ChinaDaily.com:
WASHINGTON - The H1N1 swine flu virus may have been new to humanity in many ways but in one key feature its closest relative was the 1918 pandemic virus, researchers reported on Wednesday.
Their findings could point to better ways to design vaccines and help explain why the swine flu pandemic largely spared the elderly.
"This study defines an unexpected similarity between two pandemic-causing strains of influenza," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), said in a statement.
Two studies show an important structure called hemagglutinin is very similar in both the swine flu H1N1 and its distant cousin, the H1N1 virus that caused the 1918 pandemic. Hemagglutinin is used by viruses to infect cells and gives influenza viruses the "H" in their designations.
For one study, published in Science Translational Medicine, Chih-Jen Wei, Gary Nabel and colleagues at NIAID injected mice with a vaccine made using the 1918 influenza virus - which killed an estimated 40 million to 100 million people.
When they infected the mice with H1N1 swine flu, the vaccinated mice survived, while many unprotected mice died.
The reverse also worked - when they immunized mice using the 2009 H1N1 virus, and then infected them with the 1918 strain, the mice were protected.
"This is a surprising result," Nabel said. "We wouldn't have expected that cross-reactive antibodies would be generated against viruses separated by so many years."
The team also showed that as flu viruses circulate, they develop a kind of shield called a glycan that protects them from the body's immune system. That may allow them to become regular, seasonal visitors.
"It gives us a new understanding of how pandemic viruses evolve into seasonal strains, and, importantly, provides direction for developing vaccines to slow or prevent that transformation," Fauci said.
This type of experiment was performed in 2009, with similar results. I believe Kawaoka did this type of work. Webster may have done it also. It reinforces the concern that one or two teeny little changes might really turn this virus into a nasty, nasty bug.
Policy makers, or persons who still labor under the false assumption that H1N1(2009) was a "false pandemic," would do well to examine the CIDRAP report. Examine, and pray this virus does not mutate or evolve into anything more closely resembling its ancestor. Because it's uncomfortably close already.