A Word on Vaccine Safety

January 10, 2008

Since I started this blog with a vaccination calendar, I’m going to weigh in briefly on the thimerosal issue. The preservative thimerosal has been removed from most children’s vaccines but remains in the traditional flu vaccination. The FluMist nasal spray does not contain thimerosal. In the past decade or so many parents of autistic children have expressed concern that there is a link between the thimerosal in vaccines and autism. I recently attended a conference (American Medical Writers Association) here in Atlanta where I attended several seminars and discussions dealing with this issue. Emory University, the CDC (Centers for Disease Control), NIH (National Institutes of Health) and many other public health organizations participated in this conference. I attended every session that had anything to do with vaccinations. Based on what I heard from this conference, my own research, and more importantly the consensus of every legitimate Public Health Organization, there is nothing to indicate that there is any correlation between the two.


Studies have been performed by parties with a wide range of interest in this subject including by the pharmaceutical companies themselves whose interest would clearly be self serving. But researchers at teaching facilities, the CDC, and the NIH have all tested this hypothesis and no one is finding a link. This article published by the New England Journal of Medicine compiles several studies with these results:

“Among the 42 neuropsychological outcomes, we detected only a few significant associations with exposure to mercury from thimerosal. The detected associations were small and almost equally divided between positive and negative effects…

and comes to this conclusion:

“Our study does not support a causal association between early exposure to mercury from thimerosal-containing vaccines and immune globulins and deficits in neuropsychological functioning at the age of 7 to 10 years.”

Genetic Polymorphism

At the conference there was some intriguing informal discussion of a possible link through genetic polymorphism which vaguely means the tendency of a certain gene (associated with neurological deficits or autism), if present, to mutate detrimentally in the presence of a certain substance (thimerosal). In other words, for those who are genetically predisposed to develop a disorder on the autism spectrum this tendency may be triggered or exacerbated by the introduction of the substance thimerosal into the system. It seems like a somewhat plausible theory which as of yet has not been substantiated or similarly obliterated by research findings. Even if this theory were to eventually be substantiated it would affect only a tiny portion of the general population and account for a small fraction of autism cases.

Confirmation Bias

From my understanding the reason so many parents are convinced that there is a link between the two has to do with the timing of the MMR shots (Measles, Mumps, and Rubella usually given in a simultaneous combination). This shot is given to most children at around 18 months. Often the diagnosis of autism is made between 18 months and 3 years of age. Several parents claim to have observed a distinct change in behavior in their child after this particular vaccination. Once these groups of parents found each other (many on the internet) a strong faction coalesced that eventually led to the CDC and the AAP (American Academy of Pediatrics) recommendation for removal of thimerosal from vaccines. Both of these organizations have since maintained the safety of thimerosal in childhood vaccines based on scientific evidence.

This recommendation was based on only anecdotal evidence which can be very emotionally persuasive but really has no bearing on scientific evidence and is usually viewed by most scientists and physicians as nothing more than a coincidence. This dismissal often has the unfortunate effect of alienating the other party (in this case the parents) who then become defensive and are pushed further down the path of confirmation bias.


One of the pieces of information that was the most illustrative to my understanding of vaccine safety was the distinction of different kinds of mercury.

For instance different types of alcohol have different effects on the human system:

Methyl alcohol = antifreeze = death

Ethyl alcohol = vodka = intoxication

The same also applies to mercury:

Methyl mercury = toxin = brain damage

Ethyl mercury = thimerosal = vaccine preservative

Of course the effects of all of the above substances on humans depend largely on the dosage.

Patient Education and Communication

One of the most important things that I see missing is from the patient education handouts you are given when your child is about to receive vaccinations. The form explains what the risks of vaccinating your child are – usually soreness at the site of injection and sometimes fever. The information I would like to see included are the risks of NOT vaccinating your child.

  • These diseases can be devastating. This has been lost in our collective memory as much of the current generation responsible for vaccinating their own children has no direct experience with them.
  • For vaccines to work to protect the public health, rates of immunization must be maintained at certain level to protect what’s known as community immunity.
  • The timing of vaccines is important. The risks carried by catching the disease are most dramatic during certain ages of a child’s development. The current vaccine schedule has been designed to optimize protection during these vulnerable windows of time.

Communication between physicians and their patients might be one of the most important and most overlooked opportunities to build public confidence and achieve ideal immunization rates. It can be exhausting, frustrating and repetitive for pediatricians to try to reeducate each parent who comes in with concerns about vaccine safety. However the pediatrician is the key point of contact between public health organizations and the public on this issue and therefore charged with this huge responsibility and opportunity.


NIH FAQ on Thimerosal http://www.niaid.nih.gov/factsheets/thimerosalqa.htm

CDC FAQ on Thimerosal containing vaccines http://www.cdc.gov/flu/about/qa/thimerosal.htm

A British MMR Fact Sheet that does touch on the risks of not immunizing http://www.mmrthefacts.nhs.uk/resources/pdf/leaflet.pdf

New England journal of medicine study http://content.nejm.org/cgi/content/full/357/13/1281

CDC announcement expanding FluMist recommendations for 2-49 year olds (up from 4-49 year olds)http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5646a4.htm


3 Responses to “A Word on Vaccine Safety”

  1. Mary Says:

    It’s very easy to “read” a study your way and see what you want to see. It’s also very important to know WHO paid for the study and that isn’t listed. It’s important to know who peer-reviewed the studies, also not listed.

    If the majority of people want to think vaccines are safe (they’re not) then so be it. I see it as a way of culling out the followers in our society.

    A baby recently died in Idaho the night of his four month old shots, foamy blood was crusted in his nose and mouth, they actually had the nerve to call that SIDS.

    A mother was recently awarded $43 million for a vaccine series that turned her son into a quadrepalegic (sp).

    My own two children were vaccine injured, and not it was not autism.

    Read through some of the reports at VAERS and you’ll come away with a whole new persepective. Are some anti-vaxxers going overboard, probably.

    But so are the vaccine makers. They have a vaccine for EVERYTHING now and it’s totally uneeded and killing our children.

    Look around you: do you know a kid without ADD, ADHD, asthma, arthritis, MS, and other autoimmune conditions like diabetes? Look around the public school and look at what we have.

    Are vaccines the only culprit? Not to me. Lack of breastfeeding. Lack of real food. Too much fast food. Too many preservatives. Too many additives. Too much polluted air and water.

    People hear that and shake their head yes, but then they say it’s SAFE to shoot your child up with formaldahyde (sp), aluminium, chick embroyos (sp), viruses (live or dead) and more. Does NOT make sense.

    Think back to your own childhood, you maybe had 3-10 vaccines before school. Today our kids get more than 30 shots, and some have 4 different vaccines in one shot (measles, mumps and rubella is three different vaccines in one shot – DTaP – Diptheria, Tetanus and Pertussis).

    Investigate Vaccine ingredients

    Read the actual inserts to the vaccines – not what they give you in the office. It’s all there. The diseases they can get, the death that can occur.

    Some will say “oh, but we are protecting the herd” – no we’re not. First, we’re not cows, second we have a totally different world than we had in the 1800s and even in the 1950s – we don’t need their toxins. But if you stop believing in vaccines they will lose their 400 BILLION

  2. Mary Says:


    400 BILLION dollar a year business!

    Think before you get another vaccine for you or your kid.

  3. […] an underlying cause – a mitochondrial disorder – that predisposed her to this development (see the Genetic Polymorphism section of my original vaccine post). Whether this condition was aggravated by the thimerosal or […]

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