That was me that said the flu had a low mortality rate... and the vast majority of flus do have extremely low mortality rates. The Spanish flu was a very specific strain that developed. I also never said that the flu couldn't evolve into something deadly.
Also, just so you know... your typical flu vaccine will do absolutely jack diddly squat against a virulent and deadly strain of H1N1 or avian flu. So when one of those strains hits... I'll be right there for vaccinations when they come up with one that will work.
My biology knowledge isn't that strong, but if I understand correctly, the more viruses you have active in the population the bigger chance you have of it mutating. Take the recent H1N1 scare. As it stood, the virus wasn't that bad, but it was clasified as a pandemic because it had spread so far. Influenza has the rare and frightening ability to mutate incredibly fast, which could lead to something innocuous becoming something much worse. Simply put, the bigger your population, the more risk you have for the really bad epidemics.
And I'm not sure what you mean with your last statement. Flu Vaccines are all made in the same way, and generally take the same amount of time from discovery to vaccination. The deadly strains can be vaccinated against just as well as the less nasty ones. At least that's how I understand it.
Edit: Been reading over previous comments. I'm pretty sure you're wrong about the purpose of the flu vaccine. Yes, its about preventing hospilization and death, but you do that by preventing as many people as possible (even those that wouldn't be hospitalized by it) from getting the flu.
Also, some numbers I ran across which surprised me:
250,000 - 500,000 people die from influenza worldwide each year.
3500 - 50,000 Americans die from influenza each year.[/QUOTE]
Influenza's genome utilizes eight segments that can mix and match to become virulent. It's yearly lifecycle involves a lot of knowledge of zoonosis and antigenic shift.
The gist is that these eight segments can mix and match to become virulent in pigs, fowl, and humans. What is non-virulent in one can be in the other. Every season a new strain crops up that is virulent in humans, it can invade you cells and cause immune response. The seasonal vaccines are comprised of heat killed virus or attenuated live virus. Depending on how fast it can be cranked out it may or may not be the current strain. H1N1 vaccination is available right now, and it's been for a while, so yes, vaccination does protect against it. I got my H1N1 last November. Vaccines use a mix and mash of various strains of influenza. The designation H1N1 for example dictates what proteins and how many that virus expresses on its protein capsid, and what is ultimately recognized by cell receptors. The H number in the name refers to the viral hemagglutinin protein, while the N refers to the type of neuraminidase enzyme on the surface of the virus. Influenza has this going on for it coupled with high density population areas like southeast asia where people interact closely and unhygenically with fowl and swine is the reason why the seasonal flu always starts in that region.
I just want to point out that azure is 100% dead wrong in what I have in bold. The current vaccine may help especially if the current seasonal virus is the same subtype as H1N1, but the fact is there is a specific H1N1 vaccine that you can receive along side the seasonal one.
http://upload.wikimedia.org/wikipedia/commons/5/5e/AntigenicShift_HiRes_vector.svg
