Hi GNP,
It doesn't really matter if H5N1 mutates. World governments are preparing for an influenza pandemic and stockpilling relenza and tamiflu accordingly.
The WHO have identified H5N1 as the most likely to cause the pandemic, but it could be any one of the many other influenza strains that create the havoc.
The stockpilling now is about insurance, Bird Flu has just sped up the process.