17 December 2009

A quick exercise in critical thinking: Vaccines and dystonia

One of my neurobiology students pointed me to a video of a women suffering from dystonia. The story very strongly implies that her dystonia was caused by getting a seasonal flu vaccine.

I’d ask anyone looking at that video to consider these things:
  1. Correlation does not imply causation. That you do a rain dance, and it later rains, does not mean you caused the rain. That she had a vaccine before the onset of her condition does not, in and of itself, mean the vaccine caused it.
  2. “Doctors say...” What doctors? There were no doctors interviewed on camera, or listed by name.
  3. No peer reviewed research was mentioned. I did a very quick search on Google Scholar, and found no papers discussing both vaccines and dystonia.
  4. What I did find was a review of people who have been diagnosed with dystonia which seems to have underlying psychological causes rather than biological causes. This indicates that there are a wide range of causes for dystonia.
Let me try to be crystal clear: I am not saying it is impossible for this particular case to have been caused by the vaccine. I am saying that the story, while emotional, isn’t informative.


Unknown said...

I found your blog through Blogger's "Blogs of Note." Great entries! Sounds like your lectures would be fun.

Liliai said...

spot on. :)