Just a point here...H5N1 is technically always changing. There are several different clades now from the original 1996 HK sequence. Thru recombination
or reassortment of gene segments and small changes in or near the domain binding site, H5N1 is gaining the ability to infect and replicate in more
kinds of bio-diverse environments, including the mamilian species (bad for us). The prevailing clade is the Qinghai Lake sequence that emerged in
China.
H5N1 is still the main canidate for a pandemic strain. It has shown a remarkable ability to adapt from avian to mamilian cells so far and has remained
viable for a longer time and has expanded it geographical range more so than other circulating viruses.
H5N1 has also aquried serveral HUMAN polymorphisms which are NOT transient in nature, as they have become fixed in the gene segments...
So I disagree here...H5N1 will still be H5N1, pandemic strain or not.
Now H2N1 or H1N1 might make a come back as a pandemic strain but they would still be H2N1 or H1N1.
Hope I got your attention. H5N1 has mine...