Jan 14 2009

Some Questions about Vaccines

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Comments: 17

This morning I received the following e-mail from Jennifer:

The above article was quite comprehensive and thoughtful but a few things haunt me. One is the fact that just because thimerosal was removed in around 2003 does not mean there will be a neat distinction in the numbers of autism (presuming thimerosal is the cause-some even see it as a symptom now of autism rather than the cause). This could be for many reasons,  including:

using up of thimerosal stocks already in existance up until the expiry date.
flu shots or multi-dose vials (containing mercury) could still be in use.
pregnant ladies are actually given flu shots and these may contain mercury
immigrant children ( from countries where thimerosal is not removed) may move to areas and be inluded in epid. studies
Also, you do not mention many shots at once and the lack of safety studies in regard to this.
Also,also, recently the mumps portion of the MMR was reduced. It was quadrupled in 1990 from what it was. This may also play a role in autism development.
What about all the kids with seizures and asthma these days. Why is MSG in the shots. EWWWW

I frequently receive similar e-mails, and similar questions appear in the comments of this blog whenever I write on the issue of vaccine and autism.  Jennifer touches on many of the current points in the moving target of anti-vaccine propaganda.

The “above article” she is referring to is Fear Not:Vaccine do not Cause Autism, which I wrote in June of 2005. While this was a fairly detailed article, it was far from comprehensive. The issue of vaccines and autism is very complex, with many relevant published studies. The article was more of an overview of the controversy. It is no also three and a half years out of date.

Here is a more recent article I wrote on the topic for Skeptical Inquirer – The Anti-Vaccine Movement, written in October 2007. It contains more information, but also is now more than a year behind the times. Of course, this blog contains many more entries on the vaccine and autism issue.

Here is an expanded version of my brief answers to Jennifer’s specific questions:

– using up of thimerosal stocks already in existance up until the expiry date.
A published inspection of 447 pediatric clinics and offices found only 1.9 percent of relevant vaccines still had thimerosal by February 2002 (Centers for Disease Control and Prevention Advisory Committee on Immunization. 2002. Practice Records of the meeting held on February 20–21, 2002, Atlanta Marriott North Central Hotel.) Those remaining few vaccines would have soon expired. So we now have a reliable 7 years after the removal of thimerosal without any decrease in the rate of increase of autism diagnoses, let alone the absolute decrease predicted by the “mercury militia.”

– flu shots or multi-dose vials (containing mercury) could still be in use.

Flu shots are optional, and even if children get flu shots thetotal dose of thimerosal from them would be much smaller than the maximal dose in the schedule in 2001. Some states, like CA, banned thimerosal containing vaccines, and many flu shots come without thimerosal. Of note, the primary source of data for the increase in autism diagnoses comes from CA, where flu vaccines do not contain thimerosal. The bottom line is this – toxicity is all about dose; the original argument for a link between thimerosal and autism was that both were on the rise in
the 1990’s, but now we have 7 years after thimerosal was dramatically reduced and the autism numbers have continued to rise without a blip. This is fatal to the thimerosal hypothesis.

– pregnant ladies are actually given flu shots and these may contain mercury

A 2007 study (Miles, J.H., and T.N. Takahashi. 2007. Lack of association between Rh status, Rh immune globulin in pregnancy and autism. American Journal of Medical Genetics, Part A1. 143(13):1397–407.) looked at the issue of exposure to mercury and vaccines during pregnancy and found no correlation with autism.

– immigrant children (from countries where thimerosal is not removed) may move to areas and be inluded in epid. studies

The data does not support this hypothesis. The number of immigrants with autism (while this is a separate and interesting question) does not account for the rise in autism diagnoses in the US. For example, the recent UC Davis study (even though I disagree with their conclusions) eliminated immigrants from the data base and showed they represented a very small number.

– Also, you do not mention many shots at once and the lack of safety studies in regard to this.

That is simply an anti-vaccine myth. Vaccines are tested both individually and as part of the overall schedule, including as multi-shots.Vaccines are tested, in fact, much more than drugs need to get FDA approval, by about an order of magnitude. Further, vaccine safety is monitored by the CDC.

– Also, also, recently the mumps portion of the MMR was reduced. It was quadrupled in 1990 from what it was. This may also play a role in autism development.

Numerous studies show no correlation between MMR and autism (MMR never contained thimerosal, btw). Vaccine constituents are monitored and tweaked as new evidence comes in. There is nothing sinister in this. This is nothing but anomaly hunting on the part of anti-vaccine
cranks who then try to imply sinister implications to facts, without putting them into any context.

– What about all the kids with seizures and asthma these days. Why is MSG in the shots. EWWWW

Asthma is on the rise. This is an area of ongoing research. So far there is no reason to link this to vaccines.

Seizure frequency rises and falls over the years, without any clear trend. Rates were higher in the 1990’s then they are today, although the last few years have seen a rise. There are rare reactions to vaccines, which can include seizures, although this is mostly due to febrile seizures – vaccine reactions can cause fever, and the fever can trigger a seizure is some children. A CDC study found “1 additional febrile seizure for every 3,000-4,000 doses (of MMR) administered.” It is important to note that febrile seizures does not equal epilepsy, and most children with febrile seizures do not continue to have seizures and do fine. In other words, there is no permanent harm.

Of note, an extensive CDC study found no correlation between vaccines and 43 measures of neurological development.

MSG is used in the manufacturing process of a few vaccines as a stabilizer. The overall dose is tiny – and again, there is no data linking this to any neurological disorders.


I don’t know if Jennifer is anti-vaccine, or is just reacting to some confusing and concerning information she picked up on the internet – the fruits of the anti-vaccine misinformation machine.   But what we see here is a manifestation of the basic strategy of the antivaccinationists – throw whatever they can against the wall, make it sound as sinister as possible, and hope that something sticks. At the very least it generates fear – it creates the uneasy feeling that something must be going on.

The “EWWWW” comment is pithy and insightful – that raw emotional disgust at the notion that there are weird chemicals in vaccines is exactly the reaction desired by the antivaccinationists. But there are chemicals in everything – the real question is, are they safe at the doses of exposure.

A critical examination of each point shows it to be invalid or a gross misrepresentation of the facts. But no matter how often we clean up their mess, the antivaccine movement will continue to find more stuff to throw against the wall.

17 responses so far

17 thoughts on “Some Questions about Vaccines”

  1. HHC says:

    I have personal knowledge of a new extended family member with a child who had febrile seizures a a result of a vaccine. She is not autistic! The child is very alert, verbal, and interactive with her environment. But the child is mentally retarded. The cause of the retardation is unknown to me.

  2. Belgarath says:

    Dr N,

    I’m curious. How long has the vaccination schedule been essentially the same?

    If the vaccination schedule has been nearly similar for 10+ years, then if vaccinations are the cause of autism, shouldn’t the autism rate have leveled off?

    In other words, since our vaccination schedule has remained fairly constant and we haven’t really added any NEW vaccines to the schedule, then the rate of autism should remain constant.

    Seems to me that those two data would at LEAST correlate if there was some sort of causal connection.

  3. Joshua says:

    The MSG comment is especially weird. Are we meant to believe that Chinese food causes autism now?

  4. Steve Page says:

    I know it’s not technically a Gish Gallop, but the brevity of that email and the size of the reply illustrates just how time-consuming it can be to correct the misconceptions of the anti-vaccinationist (or concerned member of the public who has been exposed to their misinformation) when they’re fired off so rapidly. At least this was typed, so you had the opportunity to answer each point in turn. Kudos to you for your patience, Steve.

  5. PaulG says:


    That would seem to be intuitively correct – but unfortunately, as these things almost always are – it’s a bit more complicated than that.

    What we’ve also seen over the years is an improvement, or at least (what we call in the UK), a “movement of the goal posts” in terms of diagnosis. Put quite simply, things that were diagnosed as quite different conditions, are now being diagnosed as autism.

    This is something we’ve been aware of for years, for example, Mahoney et. al., back in 1998, discovered problems in differentiating diagnoses of autism…

    “The current DSM-IV criteria show good to excellent reliability for the diagnosis of PDD, Asperger’s disorder (AsD), and autism, but they show poor reliability for the diagnosis of atypical autism. The clinician (compared to the CBE) had little difficulty differentiating PDD from non-PDD children and autism from AsD but had more difficulty identifying children with atypical autism. The latent class analysis also showed that the average error rates of the three raters for a differentiation of atypical autism from autism were unacceptably high.”

    Which means that now, statistically, we’re not comparing “like for like”, because our methods of diagnosis have changed so much and have historically contained a considerable margin of error.

    This is just one of the questions we have to deal with when we ask just how great the increase in autism really is.



    Mahoney, W. J., Szatmari, P., Maclean, J. E., Bryson, S. E., Bartolucci, G., Walter, S. D., Jones, M. B., Zwaigengaum, L.
    Reliability and Accuracy of Differentiating Pervasive Developmental Disorder Subtypes. J. Am. Acad. Child Adolesc. Psychiatry, 1998, 37(3):278-285.


  6. yith says:

    For Jennifer:

    MSG is monosodium glutamate. This is basically a soluble form of the amino acid glutamine (a glutamine molecule with a sodium attached to it). If you are worried about this then you should also be worried about aspartame with its constituent content of the amino acids phenylalanine and aspartic acid.

    So there is no need to ‘eww’ over the addition of an amino acid. The reason it is popular in some dishes is because its property as an amino acid makes it taste ‘savory’.

    But mainly my point here it to reduce the ‘eww’ factor about this additive.

  7. TheBlackCat says:

    The reason it is popular in some dishes is because its property as an amino acid makes it taste ’savory’.

    That would be true if we were rats, which have a general taste for amino acids. We cannot taste amino acids in general, only glutamate. That is why you don’t see people adding other individual amino acids to food in the same way.

  8. SDR says:

    yith, you are right, but there’s another issue behind her disgust of MSG. It is claimed, as we have all heard before, that a significant number of people get bad reactions from ingesting MSG. The fact is the data doesn’t support this.

    It is much more likely that any issues come from simply the indigestion that Chinese food, with or without MSG, can give anyone based only on the amount of spices generally included. It has also been hypothesized that it is simply a placebo reaction when one learns they ingested MSG.

    There’s no reason at all, that I have seen, for anyone to worry about MSG at all, whether in food or used in the production of vaccines.

  9. RickK says:

    I’ve often wondered about the people who choose to take the MMR as multiple separate shots rather than a single combined shot. The single shot involves fewer supporting chemicals, preservatives, etc. than multiple shots. And the number of proteins in the MMR shot is miniscule compared to the number of proteins a child is exposed to every day. The reason vaccines are important is that they contain the “right” proteins. But it’s a very small number.

    Isn’t spreading out the MMR into multiple shots actually exposing children to more of the stuff that people (mistakenly) think is so evil?

  10. drb says:

    Not to quibble, but MSG is the sodium salt of glutamate, not glutamine. Similar, but not identical amino acids, especially in terms of charge. Not sure what you are referring to with the aspartame comment; sure it is a dipeptide, but compared to the amino acid intake of an ordinary meal, it is quantitatively negligible unless you have phenylketonuria.
    My personal experience with amino acids is that they are NOT tasteless. Sulfur-containing amino acids such as methionine and cysteine are particularly unpleasant. Metabolic formulas designed for use in the dietary treatment of certain disorders of metabolism often contain mixtures of amino acids rather than natural protein (in order that one or more of the amino acids may be restricted) are minimally palatable, and present significant compliance challenges to the patients for whom they are prescribed. Of course, this has nothing to do with the implication of the writer Jennifer, that trivial exposure to MSG in the form of a minor vaccine preservative is harmful, or at least distasteful.

  11. colli037 says:

    MSG is also forms in home made stew, and is an “all natural” part of soy sauce.

    Don’t tell them about the dangers of Dihydrogen Monoxide in the vaccines either.

    waiting for the SSPE cases in measles survivors to start showing up.

  12. caly says:

    Not to keep derailing this topic with the MSG discussion, but I’d love to hear Dr. Novella’s thoughts on it.

    I personally suffer from migraines and there is so much contradictory information about what does and doesn’t cause it. I frequently wonder if I’m having actual reactions or placebo reactions. Really damn painful placebo reactions. How can you gauge that sort of thing?

    For what it’s worth, I didn’t get a headache from my recent flu or Tdap vaccines (I also didn’t catch the autism, whew!), but it usually takes a good dose of MSG to bring on a migraine for me.

  13. kevinf says:

    Amino acids absolutely have smells or taste, or possibly enhance the ability to smell or taste. I prepare yeast media all the time and certain aminos smell like pancake syrup or potato chips.

    If Jennifer fears glutamate she best have her synapses flushed. Maybe a Kinoki Hat would do the trick.

  14. Fifi says:

    There seems to be a connection between B6 deficiency and sensitivity to MSG according to some studies. Not sure how concrete that relationship is but it’s interesting to consider.

  15. TheBlackCat says:

    @ drb: It is not that they are “tasteless”, they can certainly have a taste (or smell, rather, most of what we think of as taste is actually smell or texture).

    However, humans have 5 different types of true taste that are sensed on our tongue that, with one exception, correspond to simple :

    Sweet: simple carbohydrates
    Sour: acids
    Salt: row-1 ions (mostly sodium and potassium)
    Bitter: various poisons
    Umami: glutamate

    The difference between humans and rats (as an example) is in the last one. Humans have one sort of umami receptor, a receptor sensitive to the amino acid glutamate. Rats, however, have umami receptors for every amino acid. That means they have a set of receptors on their tongues that will tell them that they are eating protein no matter what amino acids are found in that protein. For humans, however, the receptors will only tell us if we are eating protein containing the amino acid glutamate.

  16. caly says:

    @ Fifi: Even if there is a connection, the typical American diet provides sufficient B6…it’s found in meats, eggs, beans, certain vegetables, etc. I seem to recall reading that B6 deficiencies could sometimes be a concern in strict vegan diets, but otherwise it’s very rare.

    MSG sensitivity seems to be a more common complaint than a B6 deficiency could explain.

  17. Fifi says:

    caly, one would think and I can’t find the study talked about anywhere except CAM, migraine or MSG sites/blogs now so I may well be incorrect!

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