#196
Among Flubies, one of the most frustrating things is the apparent inability of the WHO and governments around the world to see the writing on the wall. Case in point: the often-stated notion that the death rate during a pandemic would run around 2%. It is from this number that the 1.9 million deaths, out of 90 million infections in the United States, has been derived.
This curious pronouncement, one that government planners have obviously crafted their contingency plans around, would seem optimistic in light of the current 60% fatality rate of Avian Influenza victims.
When asked their reasoning, officials have stated that they believe the virus would trade lethality for transmissibility. Furthermore, they bring up the old saw about a virus that is too efficient a killer is unable to spread as a pandemic. And that sounds good. And were we talking about a disease that only becomes contagious after a patient becomes symptomatic, it might even be true.
But the influenza virus is transmissible for up to 48 hours before the patient shows symptoms, giving the virus plenty of opportunity to be transmitted before killing off the host.
Well, today, the WHO has admitted that a reduction in the CFR (Case Fatality Ratio) of the virus may not be a given. Witness this article by one of our favorite science writers, Helen Branswell of the Canadian Press.
http://www.cbc.ca/cp/health/061102/x110210.html
If bird flu virus becomes pandemic, high death rates possible: WHO report
12:30:01 EST Nov 2, 2006
Canadian Press: HELEN BRANSWELL
(CP) - There's no guarantee the H5N1 avian flu virus would become less deadly to people if it triggers a pandemic, a new report from the World Health Organization warns.
A group of eminent influenza scientists gathered by the WHO last month concluded there is no reason to believe that the virus, which kills roughly 60 per cent of people who become infected, would become any milder if it evolves to become a pandemic strain.
The report, based on that meeting, cautions governments against spending a lot of money to stockpile existing H5N1 vaccines. It also reveals that a low level of H5N1 viruses found in wild and domestic birds appear to be naturally resistant to oseltamivir, the main flu drug being stockpiled against a future pandemic.
The WHO scientist who convened the meeting cautioned, however, that the question of how lethal an H5N1 pandemic might be is the scientific equivalent of a black hole.
Modern science has never seen a flu virus as nasty as H5N1, and there is no way of knowing if the virus can become easily transmissible among people or what an H5N1 pandemic would look like.
"It's one of those things that you hate to conjecture," said Michael Perdue, an avian influenza expert and scientist with the WHO's global influenza program.
"We just don't know enough about this virus, a whole new subtype for humans. . . . If a new H5 enters, it could be more lethal than anything we've ever seen in history. (But) who knows?"
"I think it's anybody's opinion because it's just so completely unknown."
The report noted some modelling studies suggest a highly lethal virus could not spark a pandemic, because people who fall gravely ill aren't walking about transmitting flu to others. "All such matters remain difficult to predict," the report concludes.
It also questions the wisdom of stockpiling current versions of H5N1 vaccine for later use, saying there is little evidence that a vaccine against one variant of the virus will induce a good immune response against even other currently circulating H5N1 viruses, let alone future ones.
"We still don't have the data that would say that a pre-pandemic vaccine based on one H5N1 strain would completely protect against another," Perdue said from Geneva.
"Although one would hope it would mitigate the effects some, we don't have the data to show it."
The United States and Switzerland are stockpiling current H5N1 vaccines. And several other countries - Singapore and Britain among them - are reported to be in negotiations with vaccine maker GlaxoSmithKline to buy bulk lots of its H5N1 vaccine for stockpiling purposes.
For the WHO, this is a major admission, and one I’m sure they weren’t thrilled to make. For those of us who have followed the Avian Flu story for the past couple of years, it’s more of a confirmation of what we have long instinctively `known’; the idea that a 2% fatality rate was a worst-case scenario is ludicrous.
Hopefully governments will now take a higher mortality rate into their planning considerations. But I doubt it. I expect them to ignore this report, because it is simply too inconvenient. A 10% or 20%, or god forbid, a 60% mortality rate would be disastrous.
And no one is likely to have the political courage to plan for that.
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