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Bird Flu

In January, Jane posted this great informational bit on bird flu. If you haven’t looked at it and you’re still under the mistaken assumption that eating chicken will give you bird flu, take a look. She lays it out very plain and simple, although she shows a bit of optimism that I’m not too sure I agree with.

While I share her assessment that the species jump from birds to humans is a very difficult and unlikely one, and the jump from bird-human transmissability to human-human transmissability is a tough leap to make, I do think that its more or less inevitable for two reasons:

  1. Flu viruses mutate RAPIDLY. That’s why you have to get a new flu shot every couple of years. This is something I intend to touch on in a bit, but suffice to say, the virus’s capacity to mutate rapidly will make it more likely to jump species especially since…
  2. Human population density is high, and a large chunk of the world (even though us sheltered Westerners oftentimes forget it) lives in reasonably close contact with animals. Yes, the recent onslaught of bird flu news on the media is more due to people actually paying attention and the media liking to blow things out of proportion, but the fact that we have such dense, mobile populations of humans, especially in close proximity to animals which are oftentimes killed in unsanitary and unclean fashions (remember SARS? not a big deal of a disease, really, but we got it b/c of improper animal killing and preparation). Moreover, research into corpses and medical information from the huge 1918 flu epidemic which probably is a reason the World War I period had such a high death toll suggests that it was a flu virus which jumped from bird to human, so this isn’t without historical precedent.

The big issue, though, isn’t whether or not the virus jumps species. The issue is whether or not we can control such an outbreak. Today’s world is very globalized and inter-connected and people (and animals) are highly mobile and impossible to contain. Most countries don’t even have pandemic control plans in place. Moreover, since the species jump will probably most likely happen first in a poorer country, little money is available to implement pandemic controls.

The drug situation is also ABYSMAL. For starters, the pharmaceutical industry has no real incentive to produce flu drugs, for two reasons:

  1. Kleenex is cheap. It sounds silly, but it was the reason Vicki Sato (former president of Vertex pharmaceuticals) gave as to why flu drugs aren’t made. For the most part, the accessibility of the vaccine, the high probability of survival with minimal complications (other than feeling really sick for a couple of days), makes people not really want to spend lots of money on flu drugs, making it not a very smart business bet for the pharmaceutical industry
  2. Recent eminent domain acquisitions and the threat of activists around the world to seize flu drugs (ie Taiwan’s ignoring Roche’s patent on Tamiflu) makes it doubly unlikely that pharmaceuticals are going to create a drug which they know they won’t be able to sell for political reasons.

So, that leads us to the drugs and vaccines that we have now. In terms of a vaccine, we are so far away from that its not even funny. We first need a clinical isolate of the virus, then we need to be able to grow it, then we need to be able to know which strains are going to infect people, and then we need to do very long clinical trials even if the FDA is on your side and is trying to rush things along. Moreover, our current methodology of mass-producing vaccines relies on enormous quantities of eggs and specialized equipment — a break in the supply chain (aka like the one recently which prevented Chiron from getting enough flu shots to the US) would completely screw the effort.

With regards to the drugs that we do have, there are two classes. The amantadines and the neuraminidase inhibitors. Frankly, they suck. The amantadines have been in use since the 60s/70s I think, and it has been shown that not only are they highly toxic (they’re teratogenic and they cause Central nervous system problems), but resistance emerges rapidly. Recent studies have also shown that, whether a product of genetic drift or by uneducated Chinese farmers throwing amantadine into their chicken feed (I’m not even joking), many of the viruses out today are resistant to amantadines.

The neuraminidase inhibitors are slightly better in that they are not as prone to resistance because most of the resistant viral strains show a compromised ability to reproduce and spread. But, sadly, there are only two drugs, Tamiflu and Relenza. Both drugs have only been shown to be effective if given prophylactically (ie before one gets the flu) or within 48 hours of infection, and they only manage to reduce duration of symptoms between 1 to 2 days and ONLY if given during that critical time (so, if you start feeling really sick, its likely already too late). The drugs themselves are very expensive, and in the case of Tamiflu is synthesized from a naturally derived compound which is in limited supply (Shikimic acid). This is no joke, as apparently Roche has literally bought up the entire world supply, which really comes from apparently four provinces in China which harvest the plant that produce it, the star anise. As for the other drug, Relenza, GSK has stopped making it due to production and formulation problems, as well as very low demand given its price and limited effect.

Not a pretty picture…

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