Reading what others have to say about it, and hearing stuff on the news and online, I have been thinking about this stuff lately. Here are my thoughts:
The new H1N1 vaccine is made the same way that seasonal flu shots are made, so it is as tested/untested as seasonal flu shots. It could have been included in this years regular flu shot if it had started a bit earlier. Medically it is no scarier then the yearly shot. It is different from the H1N1 shot in the 70's that had neurological side effects, medical science has come a long way in making vaccines since then. Every year the flu shot is a mix of new flu variants, and is not tested widely before distribution. And has very few side effects. That said it is not impossible for any years flu shot to have some unpredicted side effects, but this one does not have any larger chance.
The reason that H1N1 flu is so scary is that it is very contagious, and has an occasional really bad course. Those bad cases have involved issues with the lungs, and they are more likely (but not only seen) in people with preexisting conditions of the lung and pregnancy. And they are bad enough to be very scary, because they reduce the amount of oxygen your body gets. Lowered oxygen can mean brain damage. It can also cause organ damage/failure, which can lead to death. Again with a caveat, most cases are mild and this does not happen. It is just hard to predict which cases will go downhill. Pregnancy or lung issues can increase the chances, so can being in your 20's and having a really heathy immune system, or having a weakened system, or being really young. Like I said, the prediction of who will have issues is not possible.
Why is it so contagious? The first reason is evolution, the contagious virus wins the race. Flu viruses are found in many species, human, dog, pig, bird, horse . . ., and they can often infect more then one species, but usually don't hit the second species as hard. But, sometimes, an organism is infected with more then one virus, and they share information, the strongest virus that emerges from the sharing spreads quickly in the single organism, and if the new combination is very contagious, it spreads throughout the population. The second reason is that this is a novel virus, no recent flu virus that has circulated in human population recently has created antibodies that are also effective against this one, so there is very little resistance to it. The H and N antigens are not the only ones, so other H1N1 viruses are not identical to this one, and don't always offer co-immunity. The only people who seem to have natural antibodies against this one are over 70 or 80 years old. The H1N1 that was circulating in the 70s does not seem to offer much if any protection against this one.
So if we look at this all together, should you get the vaccine? On an individual level, as with any vaccine, you have to look at how likely you are to get the illness (quite high in many areas), how likely you are to have a bad course (low, but not zero), and how likely you are to have a bad reaction to the vaccine (low, unless you have a specific reason, such as egg allergy), and how likely you are to give the virus to someone else who could have a bad reaction, and you need to weigh these against each other. You also have to decide if the risk of mild reaction to the vaccine is worth avoiding a mild illness. Personally, I think that the risk-benefit analysis should use mostly the really bad and deadly consequences, the mild ones are just that, mild.
On a population level the best thing would be for everyone who can get the vaccine to get it, so that the flu does not spread quickly. Then the people who can not get the vaccine will then be less likely to get the flu because it will not be around as much, so they will not get exposed. This is the principal of herd immunity.
Now, what is the individuals responsibility to society? The more people that are vaccinated, the less likely it is for it to spread, so the fewer bad cases, fewer deaths. For any individual the best scenario is for them to not have the chance of vaccine reaction, not getting the vaccine, but for everyone else in the community to get the vaccine so they also don't have a chance of catching the illness. This is a variation on the prisoner's dilemma. If everyone follows the most self-serving path, then everyone loses. I would maintain that the individual has some responsibility to society, not just getting vaccinated, but also stopping at stop signs, not shooting your gun in the direction of your neighbors house, and all those other things that might inconvenience us but help to protect our neighbors.
What does this mean about other vaccinations? That the risk-benefit analysis should also be done, not only on a personal level, but on a population level. I think that an almost religious zeal in believing that everyone should get every vaccination is dangerous, as is the same thing in the other direction. The truth is that we don't know if some of the current vaccinations cause things like an increase in allergies, autoimmune diseases, neurological/behavioral conditions, chronic fatigue, fibromyalgia, and all those other things that are thought of as "modern medical issues". We also don't know if high fructose corn syrup causes it, or pollution, or wearing polyester. And even if it turns out that vaccination can cause painful purple spots (pps) (or any other thing) we have to look at what it is preventing, if 5,000 people will die from a disease, or 10,000 will get non-lethal pps, what is the best course of action. If we can predict who is more likely to get pps, then they can avoid the vaccine, and everyone else getting it can offer herd immunity to protect them, that would be the biggest benefit to society. But we are not at that level of knowledge. There is no condition, other then acute allergic reaction, that is reliably tied to vaccination. You also have to look at whether the reaction is better or worse then the disease that the vaccine prevents.
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