The Data: Vaccines and Autism
Over the last two weeks I’ve dealt with the issue of vaccines as they pertain to Autism. I first dealt with the back story and then addressed why such an illusion of cause has persisted despite the efforts of the scientific and medical communities. Although I have made reference to some of the data, I thought it would be prudent to put forward some particularly relevant facts and statistics.
First, I would like to note the progress mankind has made with regard to average life span and give credit where credit is due. Carl Sagan, in his excellent book, The Demon-Haunted World, addressed this very issue indicating that in pre-agricultural times, 10,000 years ago, human life expectancy was about 20-30 years. That expectancy persisted throughout the rise and fall of the Greek and Roman empires right through Medieval times. Not until the late 19th century did it rise to 40 years. In 1915 it was estimated to be 50 and then as high as 60 by 1930. It rose to 70 in about 1955 and is currently around 80 for individuals living in developed countries.
So what can we attribute this growth in life expectancy to? The answer is clear. Along with advancements in public sanitation (clean water, flush toilets) and vast improvements in nutrition, science has contributed the germ theory of disease and huge advancements in medical care and medical technology. Of particular importance has been our increased capacity to understand and prevent infectious diseases. Understanding how diseases spread has been important in minimizing the spread of illnesses like TB and it continues to be important with regard to HIV; however, another huge variable has been the introduction of immunizations.
Not all that long ago, infectious diseases were among the top causes of death for humans in developed nations. And this is still the case in many low income countries. According to World Health Organization statistics, six of the top ten causes of death in low income nations include infectious diseases (respiratory infections 11.2%, Diarrheal diseases, 6.9%, HIV/AIDS 5.7%, TB 3.5%, neonatal infections 3.4%, and Malaria 3.3%). Whereas in high-income countries, heart disease, cerebrovascular disease, and cancer reign supreme. The only infectious disease to make the top 10 in high-income countries is lower respiratory infections (3.8%). Although heart disease, strokes, and cancer afflict the 3rd world, the proportion of deaths attributable to infectious diseases dominates. This discrepancy is essentially due to publicly managed vaccine and infection control programs affordable only to relatively wealthy industrialized nations.
If you look back in time at US morbidity and mortality statistics (Roush, Murphy, & the Vaccine-Preventable Disease Table Working Group, 2007) pre- and post-mandated vaccines, the numbers are staggering. The peak annual death rates for diseases like diphtheria was 3065 (1936), measles 552 (1958), mumps 50 (1964), rubella 24 (1968), pertussis 7518 (1934), polio (paralytic) 3145 (1952), and smallpox 2510 (1902). The peak morbidity rate for diphtheria was 30,508 (1938), measles 763,094 (1958), mumps 212,932 (1964), rubella 488,796 (1968), pertussis 265,209 (1934), Polio (paralytic) 21,269 (1952), and smallpox 2510 (1902). In 2004 (the post mandated vaccine era) there were no (zero) deaths in the US attributable to diphtheria, measles, mumps, paralytic polio, rubella, and smallpox. Pertussis persists, having killed 27 people in 2004, afflicting over 15,000 in 2006. Regardless, in the US, our vaccine schedules have essentially eradicated infectious diseases that previously took thousands of children’s lives every year. There has been more than a 92% decline in morbidity and a 99% or greater reduction in deaths attributed to preventable infectious diseases targeted since 1980 by the current vaccine schedule. Endemic transmission of measles, rubella, and the poliovirus have also been eliminated and smallpox has been eradicated worldwide. This is no small accomplishment. One must keep in mind that one who fails to learn from history is doomed to repeat it (Crislip paraphrasing Santayana).
The objections to vaccines put forth by the anti-vaccine folks have morphed over time. The initial notions included the presence of mercury (thimerosal) in the vaccines and the vilification of the MMR vaccine itself. Both of these notions have been debunked. The new themes include too many too soon and the presence of other toxins in the vaccines.
In my previous post, The Illusion of Cause – Vaccines and Autism, I addressed the innate human propensity to draw causal relationships between vaccines and Autism. I noted that despite the removal of thimerosal from routine childhood vaccines, the numbers of incidences of Autism continues to rise. And I discussed the fact that thimerosal contains ethyl-mercury which poses far less risk than the more dangerous fat soluble methyl-mercury. Eating a six ounce chunk of tuna exposes one to 8959 micrograms of methyl-mercury while the maximum cumulative exposure to mercury through the first six months of life (before the removal of thimerosal) was around 187.5 micrograms of ethyl-mercury (Crislip, 2010). The research has been clear: there is no plausible association between mercury toxicity or even other heavy metal exposure and Autism (Science in Autism Treatment, 2009). In particular, a study published in 2007 in Research in Autism Spectrum Disorders by Williams, Hersh, Allard, and Sears found no significant difference in the levels of mercury detected in hair samples between children diagnosed with Autism and their un-afflicted siblings. Regardless, thimerosal has been removed from routine childhood vaccines (except some influenza and some tetanus multi-dose vials) not due to safety concerns but to reduce non-compliance issues associated with unwarranted fear. Thimerosal is a non-issue.
With regards to the MMR vaccine – I previously discussed how Andrew Wakefield misrepresented his personal conflicts of interest and intentionally manipulated the data to support his contention that MMR causes Autism. Study after study, many of which were large scale epidemiological studies, failed to replicate Wakefield’s findings. And what is even more interesting is that some studies suggest that the MMR vaccine is actually associated with decreased incidences of Autism in recipients versus non-recipients (Mrozek-Budzyn, D., Kieltyka, A., and Majewska, R. 2010). This is likely background noise and may not pan out in other studies, but…….. In Jackson County, Oregon 15% of the children have not been vaccinated. Within Jackson County, in the city of Ashland, 25% of the children are not vaccinated. The rate of educational diagnoses of Autism in Ashland is 1.1% – which is the highest rate in the county and above the state average (Crislip, 2010). So the population where there is the lowest rate of vaccination also includes the highest rate of Autism diagnoses. One has to be careful not to fall victim to the illusion of cause with this data.
Too Many Too Soon is the new mantra, railed by the anti-vaccine set: but this argument is easily assuaged by gaining a better understanding of the microbiome. Mark Crislip, MD, an immunologist, effectively puts this issue into perspective in his podcast The Vaccine Pseudo Controversy. Crislip notes that for every human cell in the human body there are 10 bacteria cells along for the ride. We are essentially a host organism for 100 billion bacteria representing several thousand species. Although a human baby is born free of such organisms, by the end of the first year of life, a typical baby has been exposed to perhaps billions of such organisms. Many of these bacteria are essential for our survival, but many are in fact pathogens kept at bay by the immune system. Extremely conservative estimates suggest that on average, a child is exposed to at least one pathogen each day just as a function of living. That being said, the vaccine schedule represents 0.694% of the antigen exposure of a six year old. As Dr. Crislip is fond of saying, the vaccines constitute a mere drop in the bucket in terms of the total number of pathogens endured just as a function of living day to day. Seriously, have you ever been around a baby? They crawl around on the ground and mouth everything they can get their hands on. A drop in the bucket indeed. Dr. Crislip notes that “the only thing a delay in vaccination does is increase the time the child is vulnerable to infections” and, I would add, weaken herd immunity. As for evidence, consider a recent study published in Pediatrics by Michael J. Smith, MD and Charles R. Woods, MD, entitled On-Time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes. An excerpt of the abstract reads as follows:
OBJECTIVES: To determine whether children who received recommended vaccines on time during the first year of life had different neuropsychological outcomes at 7 to 10 years of age as compared with children with delayed receipt or nonreceipt of these vaccines.
METHODS: Publicly available data, including age at vaccination, from a previous Vaccine Safety Datalink study of thimerosal exposure and 42 neuropsychological outcomes were analyzed. Secondary analyses were performed on a subset of children with the highest and lowest vaccine exposures during the first 7 months of life.
RESULTS: Timely vaccination was associated with better performance on 12 outcomes in univariate testing and remained associated with better performance for 2 outcomes in multivariable analyses. No statistically significant differences favored delayed receipt. In secondary analyses, children with the greatest vaccine exposure during the first 7 months of life performed better than children with the least vaccine exposure on 15 outcomes in univariate testing; these differences did not persist in multivariable analyses. No statistically significant differences favored the less vaccinated children.
CONCLUSIONS: Timely vaccination during infancy has no adverse effect on neuropsychological outcomes 7 to 10 years later. These data may reassure parents who are concerned that children receive too many vaccines too soon. Pediatrics 2010;125:1134–1141
And then there is the contention that there are toxins in the vaccines. Well this is undeniably true. The Center for Disease Control makes known the additives for each vaccine. The list may initially seem foreboding, but the CDC and Dr. Crislip, as well as others consulted who posses far more expertise than I, attempt to assure us that these additives perform important functions and pose no notable risk. The CDC notes: “Chemicals commonly used in the production of vaccines include a suspending fluid (sterile water, saline, or fluids containing protein); preservatives and stabilizers (for example, albumin, phenols, and glycine); and adjuvants or enhancers that help improve the vaccine’s effectiveness. Vaccines also may contain very small amounts of the culture material used to grow the virus or bacteria used in the vaccine, such as chicken egg protein.”
The CDC notes that Common substances found in vaccines include:
- Aluminum gels or salts of aluminum which are added as adjuvants to help the vaccine stimulate a better response to the vaccine. Adjuvants help promote an earlier, more potent response, and more persistent immune response to the vaccine.
- Formaldehyde is used to inactivate bacterial products for toxoid vaccines, (these are vaccines that use an inactive bacterial toxin to produce immunity.) It is also used to kill unwanted viruses and bacteria that might contaminate the vaccine during production.
- Monosodium glutamate (MSG) and 2-phenoxy-ethanol which are used as stabilizers in a few vaccines to help the vaccine remain unchanged when the vaccine is exposed to heat, light, acidity, or humidity.
- Thimerosal is a mercury-containing preservative that is added to vials of vaccine that contain more than one dose to prevent contamination and growth of potentially harmful bacteria.
A little more knowledge is helpful. Did you know, for example, that “the average person produces about 1.5 ounces of formaldehyde each day as a part of normal metabolic processes[?]” (Crislip, 2010). It’s true. And as a result, there is a low steady state of formaldehyde in human blood at a concentration of 1 to 2 parts-per-million. The concentration of this additive in vaccines is actually at a lower level than is naturally occurring in your blood. Dr. Crislip notes that by far, the deadliest additive in vaccines is dihydrogen monoxide – which is responsible for nine deaths a day in the US. Otherwise, if you accept the dose-response effect of chemicals and the microscopic doses of the additives in vaccines, you will rest assured that vaccines are safe and serve a very important life saving role in our civilization. The bottom line comes down to belief systems. If you believe something so fully that you are unwilling to put a skeptical eye on it and reject it, if the evidence does not support it, then you are rejecting reality in support of unsubstantiated ideology. Always be wary of unsubstantiated ideology! Oh and the dihydrogen monoxide – that’s water (H2O).
Association for Science in Autism Treatment. (2009). Autism & Vaccines: The Evidence to Date. Vol. 6., No. 1 http://www.asatonline.org/pdf/summer2009.pdf
Center for Disease Control. Basics and Common Questions: Ingredients of Vaccines – Fact Sheet. http://www.cdc.gov/vaccines/vac-gen/additives.htm
Crislip, M. (2010). The Vaccine Pseudo Controversy. Quackcast # 45. http://www.pusware.com/quackcast/quackcast45.mp3
Mrozek-Budzyn, D., Kieltyka, A., and Majewska, R. (2010).Lack of Association Between Measles-Mumps-Rubella Vaccination and Autism in Children: A Case-Control Study.Pediatric Infectious Disease Journal. 29(5):397-400.
Roush, S. W., Murphy, T. V., & the Vaccine-Preventable Disease Table Working Group. (2007). Historical Comparisons of Morbidity and Mortality for Vaccine-Preventable Diseases in the United States. JAMA. 298(18):2155-2163 (doi:10.1001/jama.298.18.2155) http://jama.ama-assn.org/cgi/content/full/298/18/2155
Sagan, C. (1996). The Demon Haunted Word. The Random House Publishing Group: New York
Smith, M. J. and Woods, C. R. (2010). On-time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes. Pediatrics published online May 24, 2010; DOI: 10.1542/peds.2009-2489 http://pediatrics.aappublications.org/cgi/content/abstract/peds.2009-2489v1
Williams, P. G., Hersh, J. H., Allard, A., and Sears, L. L. A controlled study of mercury levels in hair samples of children with autism as compared to their typically developing siblings.” Research in Autism Spectrum Disorders. 16 May 2007, Volume 2, Issue 1: 170-175.
World Health Organization. (2004). The 10 leading causes of death by broad income group. Fact Sheet No. 310. http://www.who.int/mediacentre/factsheets/fs310/en/index.html