With the ongoing 2009 novel H1N1 influenza virus outbreak and the recent availability of vaccine for said virus, there has been much discussion on various websites and blogs about both the disease and the vaccine.  As always with medical things, misinformation, rumor and fearmongering abounds.  There are persons convinced that this outbreak is nothing to worry about at all, so neither they nor their children will be vaccinated.  There are persons convinced that the vaccine is completely experimental and/or that the vaccination plan is mostly a government ploy to poison us all. There are persons convinced that the disease is a serious threat to their health and they're upset they cannot get access to the vaccine faster.

I find it amusing that some persons who get the seasonal influenza vaccine each year are refusing the H1N1 vaccine because they believe it to be untested.  This is amusing to me because the H1N1 vaccine was tested (largely for immunogenicity).  The seasonal influenza vaccine produced each year is NOT tested each year for either safety or immunogenicity.  It was approved by FDA years ago, but each year's version does not undergo further testing.

When vaccine development first began, there was considerable discussion as to whether or not the vaccine would contain an adjuvant (a compound which stimulates the immune response). The advantage of an adjuvant is that a smaller amount of antigen can be used to produce the same strength immune response as a larger dose of un-adjuvanted antigen.  The reason adjuvant was considered was that half the amount of antigen currently used in the vaccine could be used, yet still produce a good immune response.  In other words, what is now expected to be 20 million doses of vaccine by November could have been 40 million doses of vaccine.  More vaccine doses in the same amount of production time.  In the U.S., the only approved adjuvant is alum (an aluminum salt) and the influenza vaccines (seasonal or H1N1) in the U.S. do NOT contain any adjuvant. The package inserts for the vaccines (with ingredients lists) are available for perusal at the Food and Drug Administration website.

If you don't want the version of the vaccine with a thimerosol preservative, then request the injectable vaccine which is packaged in pre-filled syringes or choose the nasal spray version.  If you are convinced that the ingredients lists are nothing but lies, you might consider giving up all food, drink and medication as all of those products have ingredients lists that could also be lies. If there's going to be a big conspiracy to kill/drug us all, why would the government and/or big corporations just limit it to vaccines?

The Part About Risk
The biggest argument I have seen against vaccinations (whether for influenza or other things) is the concern about the risk of adverse reactions/side effects.  Yes, there is a non-zero risk of problems with vaccines.  There is a non-zero risk to everything, including the peanut butter sammich I am presently eating for lunch, the pseudoephedrine I took this morning and the contact lenses I am wearing. What concerns me about the vaccine decision making tree is that people only seem to consider the risk of vaccination.  They don't seem to consider the risk of non-vaccination (i.e. the risks associated with acquiring the disease the vaccine would protect against).

Risk evaluation is a complex business.  I can reduce some of my risks by changing my behavior (exercise more, quit smoking, eat more fresh produce), but each of those behavior changes may increase other risks.  Exercising more may help strengthen my cardiovacular system, build muscle, prevent bone loss and help control my weight.  That same bit of exercising may also increase my risk of injury (pulled muscles, twisted ankles, etc.).  So is exercise really good for me if it increases my risk of adverse outcomes? It all comes down to whether or not you think the benefits of an action outweigh the risks. I make that risk evaluation based not only on the magnitude of the risk or benefit but also on the population-based probability of that risk or benefit occurring. (No, I cannot calculate or predict my personal probability of having an event occur. It's impossible.)  

To apply this to vaccination, consider the following: Thirty percent of all measles cases have some sort of complication due to the disease. Pneumonia occurs in about 6% of measles cases and causes about 60% of measles deaths.  The risk of encephalitis (and usually permanent neurologic damage) due to measles disease is approximately 1 in 1000.  The rate of any side effect at all due to measles vaccine is approximately 20% with the majority of those being simple fever or rash. Temporary, transient thrombocytopenia occurs in 1 person for every 30,000 to 40,000 persons vaccinated.  Encephalitis occurs  at a rate of 1 in a million.  So, do you choose a 1 in a million risk of encephalitis or a 1 in 1000 risk of encephalitis?  I know which one I would pick. Certainly I may have the misfortune of being the one in a million who gets encephalitis due to vaccine, but I like those odds a whole lot more than I like 1 in 1000.

Personally, I think it's prudent to do what I can (within reason) to minimize those risks that I can minimize.  I don't actually structure my whole life around risk reduction.  I reduce what I can within reason.  I do use peer-reviewed research to guide these decisions and often track down the original research, not just the interpretations of the research published in the media or on various websites seeking to sell the healthy cure of the week.  To that end I exercise regularly, eat lots of vegetables and fruits, avoid foods which are highly processed or high in fat, engage in relaxing activities regularly and get a reasonable amount of sleep every night. Will it make any difference in the long run? I'll never know.  I'm only a single "test subject". There is no control in this experiment called life.  I cannot know what might happen if I ate nothing but pizza, fries and cheeseburgers every day.  I might still live to be 111 and be fully active until the day I die.  Then again, even with the healthy behaviors listed earlier, I might still burst an aneurysm at any time or get killed in a car crash, making all my actions irrelevant and ineffective. I still choose to do my best to maximize my chances of a long, functional life.  Oddly enough, I don't miss the cheeseburgers and fries at all.  I thoroughly enjoy the boosts in energy and cheerful attitude that I've experienced since becoming vegetarian a couple years ago, since starting a regular gym-based workout a year ago and since dramatically changing my eating habits eight months ago.  I may or may not end up living longer, but I sure am having more fun and enjoying life more now.


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