http://www.rdi.gpo.or.th/NetZine/V3N46/flu.htm
Haven't taken the time to read it (just scanned over it quickly), but I'm certain it's the classic Scientific American article from a couple of years back about influenza. Don't know why it's posted where it is (that doesn't look like the SA site). I just searched on a couple of key words from the article and found it there.
Contrary to some opinions expressed here, the threat of a flu pandemic is very, very real, and it could kill millions. Informed and thoughtful people would take it seriously.
Incidentally, the flu strains that cause pandemics don't develop because of too many people being too close together, but because of too many people living in close proximity with animals such as poultry and swine that can have the flu.
Haven't read the article since it first came out, so my memory's a little hazy, but I think the theory is that such a flu virus is created when a host critter is infected with a human flu strain and a swine or bird flu strain simultaneously.
When a an individual flu virus invades a host cell, I believe it comes apart and releases its genetic material (8 strands of RNA, as I recall) into the cell. The RNA strands float about separately in the nucleus of the cell, using amino acids available there to create copies of themselves. Then they recombine into daughter viruses and cleave the cell wall, causing it to rupture, so they can invade other cells.
I think the theory is that if a host cell is simultaneously invaded by human flu virus and a porcine or avian virus, it's possible for strands of RNA from both viral types to recombine to create a daughter virus that's close enough to a normal human flu virus to be well-adapted to our bodies, but exotic enough that we have no antibodies that "recognize" it.<It is a truly outstanding article; I recommend it to all.
The virus exists in a multitude of forms....the vaccine for any particular year is based on epidemiologic analysis of existing cases appx. 6 months prior to the next "flu season". So, in essence, the package of viruses that you get immunized against in any one season is based somewhat on a "best guess" analysis of prevailing virus. The immunity is excellent - but only against the virus package in the vaccine. You could unfortunately encounter another type of flu virus and get sick - it doesn't mean the vaccine isn't working - you just got unlucky.
The only reason influenza is "seasonal" is because it's more easily transmitted when people are in close quarters ( ie. inside during cold weather). Also, use of indoor heat reduces the relative humidity indoors, your nasal mucous membranes tend to dry up, and they become less effective in providing a "first line of defense" against invasion by the virus.
Fatalities due to influenza are not usually directly caused by the virus, they're caused by secondary bacterial infections ( without going into too much detail, suffice to say that the virus does a nasty job on the cells lining your trachea, and these are the cells that help to "catch" bacteria as they slide down the tube toward your lungs). Most deaths are due to pneumonia. the reason there were so many deaths in 1918 was because there were no antibiotics available to fight the secondary infections. So, basically, the flu virus itself doesn't kill ( naturally there are exceptions to this ) - it's the bacteria that cause the later infections that do most of the killing.
Bottom line - if you're older or if you're a smoker - or if you come in close contact with the public ( indoors ) ....I'd say to get the shot.
P.S. : the thimerosol is a preservative - it's the same stuff you find in contact lens solutions.
Hope this helps! ( and take the tinfoil off your hats - any season has the potential to be a 'bad' season - this one's no different.....this is one thing I don't stay up nights worrying about. I'd rather not say what I DO worry about!!!!).