Thursday, January 20, 2011

Flu Vaccinations: A Short Lesson on Critical Thinking.

A friend recently asked me to critically review the following article on the influenza vaccine. Rather than spam my original facebook post I thought I would write my review here.

When you read an article like this it is always important to look at who is promoting or publishing the article. This is true of all scientific studies, but something I am more assiduous with in regards to vaccine literature. The study itself was done by The Cochrane Collaboration, which I don't know much about but seems pretty legit. It is basically a non-profit organization that reviews health care. I didn't do that much research on it so of course I could be wrong, but the reports produced by them seem to be evidence based with no particular bias.

However, it all depends on how the study is interpreted. You can always slant a review to meet your needs. In this case, the website featuring this article is far from unbiased. Gaia Health is very anti-pharmaceutical company and it looks like they don't care for mainstream medicine at all. The comments alone made it pretty evident that the people who regularly read this site would likely belong to the Wakefield fan club. So right of the bat I was alert for anti-vaccine sentiments.

The article isn't so much about the harm the influenza vaccine can cause, which is usually the case of people with this mindset, but with the ineffectiveness. If you are a healthy adult it may seem like the flu vaccine doesn't really have an effect at all, which this particular study proves. I don't doubt that. Healthy adults may not personally benefit from the influenza vaccine. So why bother?

We bother because it isn't the healthy people we should be concerned with. This article does little to report on the unhealthy people. Normally I would refer to the herd immunity defense, but surprisingly the article actually addresses that. It claims when given parenterally the vaccine does little to prevent viral infection and doesn't do much to prevent complications.

I believe the outcome to a degree. Do what you will with that information. However I always resort to third party resources. I am a huge fan of the Center for Disease Control. They bring up an important point. They state that the more non-specific the outcome being measured the lower the estimates of vaccine effectiveness. Also not addressed are the different population in which the vaccine is effect as it can widely vary.

With all vaccines it is important to weigh the risks vs benefits. This article did little to address the harmful side effects of the flu vaccine. If it turns out the vaccine itself was risky to the general population (there are always those that are more prone to adverse effects) and there were no real proven benefits I would say don't vaccinate. If the risks are small what is the harm of getting the shot either way. If it works it works, if it doesn't at least you tried. For me the jury is out, simply because based on this article alone there simply is not enough information. If you can take away any lesson from this, it should be to never resort to one source and to research your sources before you draw conclusions.

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