Wednesday, September 21, 2005

The Potential for the Next Pandemic: Avian Flu

The news on the potential mutation of the avian flu virus to the point of human-to-human transmission is grim. When (not 'if') this occurs, the threat of the pandemic may very well be realized.

Here is what the Boston Globe had to say last Saturday:

Avian flu will mutate and become transmissible by humans, and the world has no time to waste to stop it from becoming a pandemic, the head of the United Nations World Health Organization said yesterday.

Andrew Natsios, head of the US Agency for International Development, said the risk of bird flu was even worse than HIV/AIDS. He urged nations to cooperate fully and not to hide knowledge of the disease when it struck.

Even with the transmission currently at the bird-to-human stage, the number of cases reported have been climbinb, especially in Viet Nam, according to the World Health Organization. From 12/16/04 to 9/19/05, there have been 114 confirmed human cases of Avian Flu, with 59 deaths. Of those, 64 cases and 21 deaths are from Viet Nam.

The most recent recommendations from WHO are located here in PDF format. While lengthy, and detailed, it's well worth the read to see just what the experts are indicating must be done to avoid the human tragedy. The report points out that at this point, the human cases seem to be limited to rural areas in that part of Asia, usually among family farmers handling poultry. When their flocks are destroyed, the livelihood for the family is as well, so that poses one of the problems WHO faces.

Another, and equally as important facet, is that the pandemic, when it starts, will most likely be located in the poorer nations. It is at that locus that the first agressive steps will have to be taken, with hopefully sufficient supplies of antiviral vaccines.

Several international consultations on pandemic influenza have asked WHO to explore establishment of an international stockpile of antiviral drugs for strategic use near thestart of a pandemic.

Experts have suggested that aggressive measures, centred on the
prophylactic use of antiviral drugs, might contain a pandemic at its source or at least slow its spread, thus gaining time to put emergency measures in place and augment vaccine supplies. Based on results from mathematical modelling, the theoretical window of opportunity for taking such action closes quickly.

And therein lies another problem: the vaccines take time to manufacture. Wealthy nations, those in the West, have already begun ordering from the manufacturers, securing the vaccines for their own populations at a cost the poorer Asian nations cannot match. It will take an extraordinary effort to convince the West that it might be wiser to assist in the stockpiling of the vaccine in the areas where the predicted sources of the outbreak are in the hopes that the disease can be contained there.

If the outbreak is not staunched at the source, we can expect the pandemic to rival, if not surpass, the great pandemics of the Twentieth Century. The US, slow in its appreciation of this fact, has so far committed $100 million for the purchase of the anti-viral vaccine. Again, according to the Boston Globe, no one is certain just what that money has purchased in terms of doses:

But just how many doses the $100 million will buy isn't yet clear.

That's because there is contrasting research on just how much antigen much be in each dose to provide protection, explained Sanofi spokesman Len Lavenda. The range is huge -- from 15 micrograms of antigen per dose to 90 -- and the protective amount likely will wind up somewhere in between, he said.

Previously, the government has said it has stockpiled 2 million doses of bird flu vaccine.

Sanofi stored that vaccine in bulk, and the 2 million estimate assumed a single 15-microgram dose per person, Lavenda said. In contrast, the preliminary NIH research suggested it may take two 90-microgram shots to provide protection.

Simple math suggests that means the $100 million purchase could provide enough doses to protect anywhere from 1.7 million people -- "we're quite sure it's going to be a lot more than that," Lavenda said -- to a maximum of 20 million people.

The government's ultimate goal is to stockpile 20 million vaccine doses, a first wave of protection if the H5N1 bird flu strain eventually sparks a pandemic.

Hopefully, the US will, with the rest of the world, work closely with WHO within the framework of the organization's most recent report. Hopefully, it will also diligently pursue a more realistic approach to protecting this nation against the ravages of the pandemic in every way possible.


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