That amplclamp is exactly what is causing the concern about H1N1/2009 amongst the worlds experts.
A pandemic strain must meet three criteria:
1. A new virus must emerge first. This normally occurs due to antigenic drift or recombination in a host species (often swine or aquatic avians). H1N1/2009 is a whole new critter.
2. It must be novel to humans and able to cause disease therein = we have no immunity which also normally infers a high CFR (Case Fatality Rate). This is a big difference to seasonal Flu A strains. In a pandemic not just a couple of hundred thusand die. The numbers are waaaay higher for a couple of reasons!
3. It must be easily and sustainably spread between humans = have an affinity for the cells in the upper respiratory tract for aerosol infection (this is why H5N1 is not a pandemic .. it only reproduces well in humans deep in the lungs so it is hard to get it there) or able to survive for lengthy periods on surfaces contacted by multiple persons and then able to infect them. Flu A is already good at this. It is also why the main focus of pandemic prevention is on personal hygiene, hand washing, cough etiquette, learning not to touch your face etc.
An Influenza A pandemic normally occurs over an extended period and occurs in waves, each succeeding wave having a greater impact (CFR) than the last. It isn't the death toll that is the real problem for us. It is the load it places on our society in terms of already overstretched health care, supply lines, utilities etc. We are better off in care and science depth than 1918 but have nowhere near the resources to deal with the number that may fall ill in a pandemic. Today we live in a 'just in time' society. Disrupt the supply chains even a little and see what happens.
This is why the experts are worried. H1N1 has met the three criteria in spades. It will be some time before we really know if it will go pandemic or not and it will be too late to get ready once teh first wave really gets going. That is why you are being warned now. It is your choice to take it or leave it.
Cheers,
Brad