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The articles linked above raise two key issues, which seem to be lost on the media. One relates to the human vaccine program and the other relates to avian flu and recombination.
As noted below, survivors of the 1918 epidemic had high levels of the antibody over 85 years later. This indicates that immunity to influenza is long lasting and annual flu shots are necessary because the flu virus changes each year. Thus, the current policy of using the same strain of virus year after year makes little scientific sense (although of course it is easier for the manufacturer).
The human vaccine is trivalent (contains 3 flu viruses), but the recent severe flu cases are related to the newly (2002) emerging Fujian strain. In 1999 the H3N2 component of the trivalent vaccine (southern hemisphere) was A/Moscow/10/99 and the equivalent (A/Panama/2007/99) has been used since then for the northern hemisphere. The Panama strain was also used last year, even though it was quite clear that Panama was being replaced by Fujian throughout the world and cross reactivity between Panama and Fujian was poor.
This year, Fujian-like H3N2 isolates are being used in the northern hemisphere vaccine, but the bacterial contamination at Chiron has created a severe shortage. Thus, most of the people in the northern hemisphere have yet to be vaccinated with a Fujian-like virus. The use of Panama-like viruses from 1999 to 2003 makes little sense, because most of those being immunized are in the "at risk population" and they are immunized year after year with the same virus (even though immunity to the 1918 isolate has lasted over 85 years in an elderly population).
The second point that should be noted is the fact that the 1918 HA molecule causing the damage in mice is in fact a recombined gene and the havoc created in mice is similar to the havoc created by recent isolates of H5N1. H5N1 is also a recombinant (in all 8 genes) and is increasingly able to infect mammals (like mice, cats, and humans) and cause damage in multiple organs (leading to the hemorrhaging seen in human and avian H5N1 infections).
The H5N1 causing the pandemic in Asia is a recombinant that arose via multiple dual infections. In Vietnam and Thailand, many of the regional polymorphisms can be found in mammalian isolates. The lack of sufficient supplies of Fujian H3N2 vaccines increases the likelihood of more human infections, which increases the likelihood of more dual infections leading to recombination and the creation of a pandemic virus capable of efficient human to human transmission.