Autism Street

In the concluding paragraph of a recent article at Spectrum Magazine (which appears to be an interview with Robert F. Kennedy Jr.), Sarah Bridges, Ph.D, writes:

Most recently, Kennedy has been speaking out against the CDC’s claim that the thimerosal debate is dead since autism rates didn’t drop when mercury was removed from vaccines.

I was unable to find any source for such a claim by the CDC in the article, or on the CDC’s website.

But, here are a few things anyone can quickly find on the CDC’s website:

http://www.cdc.gov/ncbddd/autism/seed.htm

Study to Explore Early Development (SEED)
SEED stands for the Study to Explore Early Development. It is a 5-year, multi-site collaborative study that will help identify what might put children at risk for autism spectrum disorders (ASDs) and other developmental disabilities.

http://www.cdc.gov/ncbddd/autism/research.htm

CDC-funded Projects

Thimerosal and Autism Study (September 2008)
Using the Vaccine Safety Datalink, CDC is comparing thimerosal exposure in children with and without autism. Certified specialists are using the most up-to-date, standardized diagnostic tests to evaluate children with autism. Review of medical records and interviews with parents are also included.

Italy Thimerosal Neurological Developmental Disorders Study (to be determined)
CDC is working with researchers in Italy to study children who were exposed to different amounts of thimerosal during infancy as part of a clinical trial of whooping cough vaccines. Some of the vaccines contained thimerosal, and some did not. The original clinical trial did not study neurological developmental disorders (NDDs), but researchers now are comparing their occurrence among participants to see how the level of thimerosal exposure affects NDDs.

Thimerosal Neurological Developmental Disorders Follow-up Study (to be determined)
This study looks at the relationship between thimerosal and neurological developmental disorders. Researchers are giving neuropsychological tests to children 7–10 years of age whose vaccinations in the first year of life could have contained thimerosal. The study will compare test results among children exposed to different quantities of thimerosal from vaccines and other exposures.

Next comes a quote from RFK Jr. (first in its entirety), we’ll dissect it in a minute to see if RFK Jr. really seems to understand the relevant science.

“The CDC themselves admitted that full strength thimerosal-laced infant vaccines were being administered until at least 2003 to allow manufacturers to rid themselves of old inventories. Since autism typically isn’t diagnosed until 44 months, even if all thimerosal was removed from vaccines in 2004, we shouldn’t expect to see a statistical decline in the rates until 2009 or 2010. However, this is irrelevant since it ignores the fact that the flu vaccine contains 50 percent of the mercury that we were giving to kids before the supposed ban on thimerosal and is recommended for pregnant women and infants. The CDC’s willingness to continue injecting children with this neurotoxin is mystifying given the Institute of Medicine’s previous recommendation that it is prudent to stop the practice. Why have they changed their view? One supposition that shouldn’t be ignored is that the CDC is frightened by what would happen if we abruptly removed the toxin, leaving many people in a horrible legal position.”

Now for a closer look:

When was thimerosal reduced?

The CDC themselves admitted that full strength thimerosal-laced infant vaccines were being administered until at least 2003 to allow manufacturers to rid themselves of old inventories.

That may be true, but it does not quantify the situation at all.

“…N.I.P. estimated the amount of thimerosal in provider vaccine inventories in a survey conducted September 20, 2001 to February 20, 2002. The targets were a convenience sample of providers getting site visits from public health officials across the country. Inventory counts were done of all refrigerators for D.T.a.P., Hib, and hep B pediatric vaccines. The thimerosal classification was based on the lot number information, which was verified by the manufacturers. In September 2001, 225 sites were canvassed, and 447 by February 2002…During the visits, the providers were surveyed about thimerosal-containing vaccines in their inventories. Of the 447 interviews, 83.5 percent reported no thimerosal-containing vaccines in stock at any time since October 2001.”

Emphasis mine.

Source: CENTERS FOR DISEASE CONTROL AND PREVENTION ADVISORY COMMITTEE ON IMMUNIZATION PRACTICE, Records of the Meeting Held on February 20-21, 2002, Atlanta Marriott North Central Hotel, Atlanta, Georgia.

447 vaccine provider inventories were surveyed during site visits -  83.5 percent reported no thimerosal-containing vaccines in stock at any time since October 2001.

When should we have seen a decline?

Since autism typically isn’t diagnosed until 44 months, even if all thimerosal was removed from vaccines in 2004, we shouldn’t expect to see a statistical decline in the rates until 2009 or 2010.

2004? We know that the largest reduction of thimerosal probably occurred around 2001 and early 2002 (see above). As a whole, it’s likely that the vast majority of kids vaccinated in 2002 received nowhere near the levels of thimerosal that kids received three years earlier. In California, children vaccinated in 2002 and later, who became part of the CDDS adminstrative prevalence figures, would have entered the 3-5 year-old autism caseload cohort during 2005 and later. That’s if they were diagnosed at age 3. If they were diagnosed at age 4, the year would be 2006. Even if they weren’t diagnosed until just before age 5, the year would be 2007 (which would still include 3 and 4 year-olds). Well 2007 came and went. No detectable drop in California’s administrative prevalence in the 3-5 year-old autism caseload cohort was observed. If JKF Jr. is right about typical age of diagnosis being 44 months, the hit to the 3-5 year-old autism caseload cohort in 2007 should have been huge, if not at least discernable.

Flu shots for pregnant women?

However, this is irrelevant since it ignores the fact that the flu vaccine contains 50 percent of the mercury that we were giving to kids before the supposed ban on thimerosal and is recommended for pregnant women and infants.

Unfortuately for RFK Jr., he’s overlooked some very important data and facts in trying to make this “weaker than weak” of arguments.

Flu shots being “recommended” for pregnant women are irrelevant when compared to the CDDS data for the relevant years.

Let’s take a look at flu shot uptake estimates for pregnant women for the three years that should have most impacted the 3-5 year-old autism caseload cohort in California for the year 2007.

2002 - 12.4 ±3.9 %
2003 - 12.8 ±4.4 %
2004 - 12.9 ±5.0 %

Source

Note: there is an increase in the estimate for 2005, but children born in 2005 and later are not old enough to be reflected in the 3-5 year-old California autism caseload cohort yet. Additionally, estimates for 2006 were back down to 12.9 percent.

Source 

(Graph added 5/16/2008)

Flu shots for infants?

6-23 months

For the 2007-08 season, there is one product licensed for 6-23 month old children (the product is thimerosal-free).  Given the uptake of influenza vaccine among children < 2 years of age to date and the anticipated increase in vaccine coverage this season, CDC projects that the vaccine supply for this agegroup will be adequate to meet demand.

Up to 35 months

At the current time, sanofi pasteur is projecting that 10 million to 12 million doses of thimerosal-free vaccine in pre-filled syringes or vials will be produced for the 2007-08 influenza season. The majority of this vaccine will be in 0.25 mL syringes (indicated for ages 6-35 months) with the remainder in 0.5 mL vials or syringes (indicated for ages 36 months and older).

That’s the current info, but what about back in 2003-2005 (The years in which the kids in the relevant-to the-CDDS-data for the 3-5 year-old autism caseload cohort would have received flu shots?

Fully-vaccinated flu shot uptake looks something like this:

2003 - 8.4% (average 5 year-olds in 2007)
2004 - 17.8% (average 4 year-olds in 2007)
2005 - 20.6% (average 3 year-olds in 2007)

Source: CDC MMWR’s for the relevant years.

Addendum 5/11/2008: I originally used the fully vaccinated (influenza) average for the United States for the 6-23 months age group. Thinking that it’s likely to be brought up that data in discussion is from California, I thought readers might like to see California estimated flu shot uptake as well.

2003 - 7.5%
2004 - 15.4%
2005  - 16.9%

This is not a lot unlike the U.S. average.

End of Addendum

So better than 90% of the 5 year olds in the relevant data set were not even vaccinated. Does the increase in flu shot uptake in this age group that occurred after 2003 even matter with respect to the California data? It doesn’t seem likely given that about 80% of kids in the relevant age group are not even vaccinated during the next couple of years. But aside from that, the ones who were vaccinated were decreasingly likely to receive a thimerosal containing flu shot at all.

In September of 2002, Aventis Pasteur, Inc was approved to manufacture a preservative-free formulation of their influenza vaccine, Fluzone that contained trace thimerosal, and in December 2004, a thimerosal-free formulation of Fluzone was approved.

Source

Remember, an autism diagnosis requires an onset prior to 36 months of age. Kids in the relevant group (where a flu shot could have anything to do with autism) simply don’t seem to be likely to be receiving thimerosal containing vaccines.

The evil CDC?

The CDC’s willingness to continue injecting children with this neurotoxin is mystifying given the Institute of Medicine’s previous recommendation that it is prudent to stop the practice.

It should be mystifying with respect to autism, since kids who do get flu shots in the relevant age group seem to be receiving thimerosal-free variety.

Why have they changed their view?

Where is the evidence that their view has changed?

One supposition that shouldn’t be ignored is that the CDC is frightened by what would happen if we abruptly removed the toxin, leaving many people in a horrible legal position.

Thimerosal was pretty abruptly removed with respect to the relevant age group back in 2002. Nothing seems to have happened with respect to 3-5 year-old autism caseload cohort in California. The people in the horrible legal position may be those petitioners in the Omnibus Autism Proceedings who belive that autism is synonymous with mercury poisoning (it’s not) or that there is any science behind the “poor-excretor” hypothesis.

My prediction? Barring any radical changes in the diagnostic criteria for autism, growth in the 3-5 year-old autism caseload cohort in California will slow and maybe even level off by 2009 or 2010. This will not equal a “statistical decline in the rates”.

Additional reading may be required for full context.

http://archpsyc.ama-assn.org/cgi/content/abstract/65/1/19