It's coming time for our kids' 12 month scheduled MMR (Mumps, Measles, Rubella) shot. There's some controversy around this shot as there are allegations that there is a link between MMR and Autism. We've found strong advocates on both sides, though many more on the pro-MMR vaccination side.
The net of it is that I find it very hard to find a compelling case either way. I can find many deficiencies in both side's arguments. On one hand, there are prevention of MMR diseases. These are extremely rare in North America now. On the other hand, autism has increased significantly but there is no proven correlation with that increase and vaccination.
If you have any additional worthwhile information or links, fire them my way. The blog doesn't have comments because comment spam is out of control.
Some of the facts as best I can tell are: There has been a stunning increase in Autism in the Western world, as pointed out in California. There has been an increase in vaccination in the Western world. For a long time, Thimerosal (mercury) was used in vaccines, but this has been phased out. There are no clearly unbiased large scale studies that correlate vaccine (with or without mercury) and consistent autism diagnosis. Each study has flaws, from researchers that are compensated by drug companies that sell MMR vaccine (Denmark study) to far too small a sample size (12) and self-selected patients (original Wakefield 1998 report with many retractions).
Some questions that are obvious to me:
1. What are the rates of MMR in North America, and what are the negative side-effects such as percentage of deaths?
2. What are the rates of Autism in North America?
3. What are the causes of Autism?
4. Assuming no known causes of Autism, what are the correlations between Autism and various vaccines, Autism and vaccines with mercury, Autism and environmental factors?
5. How has the definition and diagnosis of Autism changed over the years?
6. Is there any difference between single shots of each of the MMR vaccines compared to the bundle of 3?
7. What are the affects of vaccination at ages ranging from 12 to 24 months?
8. When has Thimerosal been phased out of each of the vaccines in Canada and the US?
Some worthwhile web sites/papers:
Wikipedia's entry on vaccine controversy is a great start.
For rates, the best I can find is the CDC 1998 report saying that:
- measles is indigenously eliminated from North America but can be brought in, such as in the measles outbreak in Indiana last year. Mortality is around 1 in 1000
- rubella is low, on the order of 200 in the US in 1994-97.
- mumps is low, such as 906 reported in the US in 1995.
I'll note the drops in MMR because of vaccination are staggering:
- 1968: Mumps 185000 cases
- 1969: Rubella 58000 cases
- 1963: Measles 400 000, but virtually all children acquired measles so 3 500 000 cases.
The seminal report "California Department of Developmental Services. 1999. Changes in the Population of Persons with Autism and Pervasive Developmental Disorders in California’s Developmental Services System: 1987 through 1998. A Report to the Legislature March 1, 1999. Sacramento CA: California Health and Human Services Agency." It noted from 1987 to 1998 a 273% increase in autism cases from 2,778 to 10,360 reported cases. Their analysis indicated a sharp rise beginning for children after 1980 (graph).
Byrd et al reported in 2002 that the increase was not due to increased diagnosis of Autism, immigration, or any other discernable factor (http://www.ucdmc.ucdavis.edu/mindinstitute/newsroom/study_final.pdf)
Center for Disease Control (CDC) has links to many papers that disprove a Vaccine/Autism link, and has a page of information and links to autism research. Note the page claims that no MMR vaccine has ever contained thimerosal, and that thimerosal was used only prior to 1999. There is also a page on Thimerosal.
The FDA has a very extensive and authoritative Thimerosal page.
The Denmark study( http://content.nejm.org/cgi/content/abstract/347/19/1477%20 ) that many health care professionals use as the definitive study. The national autism association assessment of the denmark study shows a huge # of problems with the methodology including:
- 2 of the 8 birth cohorts were only 1 or 2 years old when the data records were obtained, too young for Autism diagnosis. But half of the unvaccinated group fell into these 2 cohorts, so true autism rates are under-represented.
- they never report the conclusion that Autism is 25% higher in vaccinated childre (6.1 per 10 000 from 440 000) than non-vaccinated children (4.9 per 10 000 from 96 000) .
- there is no analysis of whether families with a history of autism are avoiding the vaccine, which, if true and if children in these families did develop autism at a higher than average rate, would inflate the rate of Autism in non-vaccinated children. Considering that the numbers in this group are small- on the order of 130 - this could be a very large factor in the group size.
- there seems to be some error in the data set because the person years of the oldest cohort is far lower than the next younger group.
- children who were diagnosed with autism before they were vaccinated were assigned to the unvaccinated category. This is 10% of the unvaccinated Autism group( 13 out of 130).
Safeminds has published a lengthy analysis of the authors relationships to the SSI. SSI is the primary supplier of Vaccine in Denmark and sells vaccines and components to the US. Among the findings, 6 of 17 authors of 3 papers are direct employees of SSI.
Another rebuttal is at casiquest. It presents the case that the MMR shot is a waste of time and also the difference between mercury load in Denmark and in the US.
One interesting study was Yokohama which withdrew MMR in 1993 and had continued rise in autism. However, I note with interest the rise in autism for a year after the withdrawal, then a drop in autism, and the even bigger drop 1 year later in the "autism with regression" type. I also wonder about the relationship to Thimerosal, and what the dosage per child is from 1988 to 1996. One possible explanation is that MMR was dropped and the commensurate reduction in Thimerosal accounts from the small drop in autism.
Pharmacotherapy published a study listing a variety of studies of MMR/Autism relationships, among them the Atlanta 2004 study
National Academic Press published Immunization Safety Review: Thimerosal - Containing Vaccines and Neurodevelopmental Disorders. This study said it couldn't find a correlation or a non-correlation, and recommends against vaccines with Thimerosal. The CDC sponsored a report to evaluate evidence of MMR/autism and thimerosal/neurodevelopment disorders, and in 2004 it reported "no relationship"
Britain's Dr. Peter Fletcher, former Chief Science Officer at the Department of Health, says MMR fears are coming true
One study showing autism rates dropping with drop in Thimerosal. An interesting reference to a study that showed Autistic children having very significant changes of glutathione levels, which is necessary for the excretion of mercury. Caveat: Author is an expert witness and consultant on no-fault NVICP and civil litigation cases.