A CDC study of the effects of infant thimerosal exposure was flawed, and its findings -- far from being reassuring -- provide even more ammunition for people who worry that the mercury-containing vaccine preservative cause autism and other disorders.
That's the conclusion of David Kirby, author of Evidence of Harm. Alert readers may have noticed that I favored the reassuring interpretation of this data in my earlier post -- but I have lots of respect for Kirby, who has followed this issue more closely than I, and he makes some very good points.
Kirby notes that 70 percent of families picked to participate in the study declined, so there could have been a selection bias. (Say, for example, you're a single mom working two jobs to pay for your autistic son's care -- you don't have time to join a study.) The researchers didn't adjust for birth weight -- "which doesn't make sense, given that an 8 pound baby injected with the hepatitis B vaccine at birth was exposed to 35 times the EPA daily safety level for mercury, (calculated by bodyweight) while a 4 pound infant was slammed with 70 times the EPA level." Neither did they control for physical, behavioral, or pharmaceutical therapies: the kids were enrolled in a big California HMO, so they could have received treatments that minimized thimerosal's effects. And finding that thimerosal-exposed boys had higher rates of tics was much creepier than the CDC said, as certain tics are associated with autistic spectrum disorders -- which, incidentally, are also much higher in boys.
These are very real flaws. I wouldn't treat these objections as gospel any more than I would the study, and the failure of autism rates to drop despite the removal of thimerosal from US infant vaccines suggests that the additive's neurodevelopmental effects are not significant at the population level -- but it's good to have Kirby on the case.
The findings were reported during a CDC conference call this afternoon; the embargo lifted at 5pm eastern; most stories have already been filed, and will show up tonight -- as of this posting, Google News already has 12 -- or early tomorrow morning, written on tight deadlines by journalists who aren't intimately familiar with the research or its context (or, for that matter, by bloggers under similar pressures.)
For a reader, I can imagine how frustrating this must be. Yes they did!
No they didn't! Yes! No! Eventually, the truth will come out -- and in no small part because the data from the study is being openly shared.
That was the final point in my first post, and I'm sticking by it. The
CDC made its interpretation. Others will make their own. Somehow we'll get to the bottom of it.
CDC: Mercury in Vaccines Damaged Your Child. Or Not. [Huffington Post]
See Also:
*Image: Andy Young
*
