Reply #50: Anti-virals for Pandemic Flu [View All]

[pandemic_1918]

>>and which nations will most likely be the ones to develop, manufacture, and distribute antiviral medicines to combat H5N1?<<

The record on antivirals is not very reassuring. Two older medications, Amantadine and Ramantadine won't help, because the H5N1 in Vietnam and Thailand already has TWO resistant mutations in the M2 gene.

All that is really left is Tamiflu. Tamiflu has been tested against a wide range of influenza A sero-types. Although it is effective against human flu like H3N2, activity against H5N1 from Vietnam and Thailand is much weaker.

Tamiflu was "field tested" when tigers at a zoo in Thailand were infected by eating chickens fed to them. The zoo started with 441 tigers and only a subset were fed the chickens (and only some of the chickens were infected). When a handful of tigers became ill, they were tested for bird flu and placed on Tamiflu (double the recommended dose and double the frequency). Over the next several weeks more and more tigers developed flu symptoms. This was almost certainly from tiger to tiger spread

http://www.recombinomics.com/tiger_trans.html

eventually 147 tigers were dead (45 from flu and 102 euthanized because they were so sick).

It is likely that the 298 tigers that survived were never exposed to the virus (most of the tigers were not fed chicken and tigers were segregated shortly after initial symptoms were seen).

The above sequence of events is a good model for a human pandemic. The tigers were endangered and valuable. I'm sure the zoo tried very hard to save the sick and prevent spread. The number saved by Tamiflu was probably close to zero.

http://www.recombinomics.com/H5N1_anti_virals.html