What mutation must the avian flu experience to become transferrable between people

Factual Questions
1

My understanding of the mutation is something along these lines

http://www.fluwikie.com/index.php?n=Science.InfluenzaPrimerII

There are sialic acids found on the surfaces of alpha 2,3 galactose and alpha 2,6 galactose receptors that the H5 protein in H5N1 binds to. Bird flu can dock/bind to alpha 2,3 galactose receptors right now, but not alpha 2,6 galactose . The fear is that a virus will mutate and be able to dock at alpha 2,6 galactose receptors, and then it will be transmissible from human to human. Both pigs and humans have both alpha 2,3 and alpha 2,6 receptors, so if a pig or a human suffers from both avian flu and the regular flu at the same time, there could be genetic mixing and an avian flu that can attach to the alpha 2,6 receptor will be created.

  1. Don’t we have alpha 2,6 sialic acid receptor blockers that we could use to prevent the spread of the flu? Block the receptor and the flu can’t get in.

  2. Whats a battle?

  3. Why can’t we create antibodies for the H5 protein if it is always going to go in through the same receptor, the sialic acid on the surface of an alpha 2,6 receptor?

I don’t know tons about cellular biology so some of my info may be wrong.

2

On another note I read on another board that the current H5N1 virus has about 9-11 amino acids that need to mutate for it to be able to attach to the sialic acid on the alpha 2,6 receptor. However I don’t know which amino acids these are, what they need to mutate to or how many amino acids there are in a regular flu virus in general (I would assume millions).

3

More like a few thousand.