There has been a lot of talk lately about the alleged harmful (potential?) side effects of vaccinations/immunizations for infants and children. What are the objective arguments against immunizing?

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    @nuc - True, there are diverse opinions—but when you look into the scientific research for/against vaccines, there's no controversy whatsoever. And because of the massive amounts of misinformation constantly being pushed out, this is a question that many parents have, and are likely to continue having.
    – Dori
    Mar 30, 2011 at 9:03
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    Highly related: skeptics.stackexchange.com/questions/95/… Mar 30, 2011 at 9:23
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    If people start closing the question, because they don't like the answers. I am off. Come on, ALL questions here could then be closed for the same reasons. Parenting by its nature is subjective and argumentative. Having said that, could some one please show me any objective data against immunization?
    – user35
    Mar 30, 2011 at 13:43
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    -1, I think this doesn't fit here. I'd rather have this on skeptics.SE.
    – Zsub
    Mar 30, 2011 at 19:16
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    @nuc - Pro-vaccination does not mean Pro-Big Pharma.
    – Dori
    Mar 31, 2011 at 23:15

10 Answers 10



Update Sept 2015: Aaron Carroll more clearly and expertly answers this in his New York Times analysis "Not up for Debate: the Science behind Vaccination".

Most of the talk lately has been about how the evidence for a link between autism and MMR vaccination is fraudulent.

So, there is no scientific research that demonstrate that contemporary vaccines are harmful, with the exception of allergic reactions (commonly egg protein) and some minor side effects (fever, headache, sore arm, tears, ...). Since even minor side effects can be serious for some populations, some vaccines are not given to all patients (e.g. those who are too young, old, sick, and/or allergic; CDC Flu Vaccine Summary for Clinicians).

There is substantial evidence that vaccines keep people from contracting serious viruses and chronic diseases. For example, a series of interactive graphics from the Wall Street Journal makes this clear, like this one showing the decline in measles following the introduction of a vaccine:

enter image description here

image credit: Ben Moore

It is not possible to conclude that a vaccine will have no negative effects on health, but it is easy to estimate the probability that the net effect will be overwhelmingly positive. Vaccines are definitely not inert - otherwise they would not work. So, on the pro-vaccine side, there are many lives saved and many lives improved. On the anti-vaccine side there are minor side effects and presently undetectable and unnoticeable 'unknowns'. For the sake of being thorough, the risks of ("hospital-acquired infections") and using needles (Guidice and Campbell, 2006) are accepted as risks that are outweighed by the benefits of receiving health care.

While I can find no compelling objective arguments against vaccinating children, Dr. Sears provides a comprehensive and well referenced overview of the arguments in "The Vaccine Book". Dr. Sears proposes the possibility that it would be in the public health interest to give some vaccines at later ages and / or more spread out through time, e.g., so that a child only receives one or two in any visit. One example he gives is to question the practice of giving 1-2 day old newborns a vaccine for Hepatitis B - which is transmitted sexually and through shared needles - because the risks of a Hep B vaccine for infants and toddlers are greater than the extremely low rates of Hep B at this age, given the fact that a child of a few months or a years would be better able to tolerate the vaccine than an infant. However, Offit and Moser (2009) suggest that Dr. Sears under-estimates the risk of Hep-B by misrepresenting previous work (they also point out other flaws in the Sears Vaccine book).


Offit and Moser (2009), The Problem With Dr Bob's Alternative Vaccine Schedule, J. Ped. http://dx.doi.org/10.1542/peds.2008-2189

Giudice and Campbell (2006) Needle-free vaccine delivery. Advanced Drug Delivery Reviews, doi:10.1016/j.addr.2005.12.003

  • 11
    I will remove the downvote if you remove the sentence "There is no scientific research showing that vaccines are not harmful". This is simply not a reasonable sentence: you cannot prove that something is completely harmless, and there is plenty of research into potential side effects.
    – philosodad
    Mar 30, 2011 at 3:06
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    So obviously there is some connection. Perhaps they are trying to determine if there's a connection. Asking about something is not the same as stating that there's a connection between the thing being asked about and the (possible) problem/symptom. Apr 1, 2011 at 12:48
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    @MasterZ Remember: Correlation does not equal causation.
    – Darwy
    Apr 22, 2011 at 12:20
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    I must also say that I disagree greatly with Dr. Sears regarding the Hep B vaccine. The purpose of administering it to newborns is to protect them from exposure; and Hep B is not restricted to sexual transmission. Because most people with Hep B are asymptomatic, it is impossible to know who is infected; your daycare workers - other children at daycare or school, etc. It can be transmitted through a bite (and I know my son has been bitten more than once at his daycare), etc. If you wait to vaccinate, the chances are greater your child will be exposed or infected and have chronic liver issues.
    – Darwy
    Oct 3, 2011 at 6:16
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    @LarianLeQuella That sums up my general impression of Dr. Sears. Just about everything I've read of his work seems to be largely based on speculation under the guise of his "decades of experience", rather than scientific research, and he seems to have no hesitation to exaggerate the risks of not buying his book and following his advice.
    – user420
    Jan 2, 2012 at 13:32

I very highly recommend the book Bad Science by Dr. Ben Goldacre.
It is very relevant to your question and addresses some of the concerns you may have about Immunization.

It is also a very good book about understanding the difference between Scientific Research results and how they are published in the Media.

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    And what is the main argument this book makes?
    – hkBst
    Sep 19, 2016 at 7:16
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    @hkBst it is a several hundred page book explaining science understanding, the misuse of science by quacks and large pharma alike. There is no main argument, it just increases the users ability to understand the articles/arguments offered to them.
    – WendyG
    Jul 9, 2018 at 10:15

There is really no reason against immunisation. See http://en.wikipedia.org/wiki/Immunization. The benefits are massive. I would actually go as far as stating that denying your child immunization should be considered a crime, similar to not protecting your child with seatbelts and child seats

  • There are actually some reasons for certain populations. While, over-all, the benefits usually outweigh the risks, some do exist and some vaccinations are for relatively harmless diseases. A person with questions should speak with the child's pediatrician, and take the offered suggestions seriously (which will usually mean getting the vaccine), but I'm not sure I'd go so far as to say there is "no argument against" or that not getting them should be a "crime". parenting.stackexchange.com/questions/1513/… Jan 22, 2013 at 0:20
  • I agree that for very rare and specific cases that vaccination is not feasible, and saying that non-vaccination should be a crime is a little harsh. However, not vaccinating your child with no specific reason (I.E. allergy) on the basis of personal beliefs in certainly unethical, possibly immoral.
    – kleineg
    Jul 8, 2014 at 14:43
  • as an autistic person my fav line is "so you would rather your child dead than like me"
    – WendyG
    Jul 9, 2018 at 10:16

Here is the only medical research that I am aware of that connects immunizations with earlier onset of seizures in this disorder: http://www.onmedica.com/newsarticle.aspx?id=e7c292a8-9949-4a65-91f1-3a80d51a7f3b

This article emphasizes that the immunization does not cause the disease, but it does appear to cause it to manifest earlier.

FYI: Here is a link to an exhaustive investigative work on the source of the MMR-Autism vaccine scare. It is lengthy, but very enlightening!


The short of it is that there is none. The study that claimed a link between MMR and autism was fraudulent.

The current theory is that autism is the result of an autoimmune disease, related to rheumatoid arthritis, MS, Crohn's Disease, etc (in fact, it's known that a mother with RA or a family history of same places that woman at a greater risk for having a child with autism). The body produces antibodies that view certain brain cells as abnormal and "foreign", and attacks them.

The supposed link between autism and vaccinations can thus be explained by the vaccine's intended effect of causing an immune response in the child's body; the elevated white cell count and production of antibodies to "fight" the vaccine's disease triggers the autoimmune response. However, that doesn't mean the vaccine itself causes autism, nor that not vaccinating your at-risk kids will prevent them from developing autism. The first time your child gets sick, gets an infected scrape, or even gets allergies, the autoimmune response will kick in.

That means that if your child has the genetic predisposition to develop autism, you're damned if you do and damned if you don't. Vaccinate the child and the vaccine causes the child to develop autism; don't vaccinate the child, and the disease the vaccine would have innoculated your child against will do the same damage. Given that the genetic factors that cause autism are roughly a 1 in 110 chance in the general population, while the diseases that the vaccines prevent are a 1 in 1 shot if your child is exposed, it's madness to not vaccinate your children, especially if you don't know that you have risk factors for autism.

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    Interesting. I had not heard the autoimmune theory. Could you provide some links to sources on this theory?
    – user420
    May 25, 2012 at 20:01
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  • The research found relationships between the genetic variants that cause autism and the ones that cause MS and ankylosing spondylitis (related to RA). The evidence suggests the variants may have evolved for a similar reason as sickle cell; if you have only a few of the markers, your chance of developing AS goes down (like having a "mild" sickle cell trait helps protect against malaria), but if you have the wrong combination of the variants they cause their own problems (similar in theory to sickle cell anemia).
    – KeithS
    May 25, 2012 at 20:10
  • Great, thanks! I've added the link into the body of your answer. The question isn't really focused on autism, and as I mentioned in comments to another answer, there do appear to be objective reasons not to have vaccines unrelated to autism (not ones that I happen to agree with, but I can't completely discount them), so I can't upvote this answer here, but I really appreciate the information, and in another context I'd love to upvote it.
    – user420
    May 25, 2012 at 20:11
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    @Sarel going to school sometimes causes injury. Taking a bath sometimes causes injury. Speculation and edge cases are not the kind of data parents should be basing decisions pertaining the well being of their children on.
    – DA01
    May 26, 2012 at 16:37

While I agree with most of the other answers (i.e. there are few if any objective arguments against immunizing) I think it would be more fair to stress the possible conflict between public health which is improved by immunisation programs, and individual risk.

For example the Rubella virus is dangerous for pregnant women and unborns. Immunising girls ensures they will not get the virus later, while pregnant. By immunising boys also, the risk of a pregnant woman coming into contact with a Rubella infected boy becomes very small. But there is only a little benefit for the boy.

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    Isn’t it a benefit for the boy that they won’t catch Rubella?
    – A E
    Jul 7, 2018 at 22:37

One big logical argument against vaccinations is the law of unintended consequences. I foresee a future resembling the past where we weren't looking for mutations caused by medicines like thalidomide while we were patting ourselves on the back for reducing morning sickness in pregnant women.

Many vaccinations are for non lethal diseases while all vaccinations are promoted as life saving and there have been deaths caused by vaccinations.

Myself and others are against all mass medication like fluoride in drinking water and vaccinations.

The statistics for reductions in diseases are often shown on graphs that start when the vaccine was created and don't show that the particular disease was declining before the vaccine started being used. This misrepresentation should be cause for concern.

The power money and corruption that we see time and time again from large rich powerful corporations happens with the pharmaceutical companies also. Would you have let enron inject your children with anything?

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    This is an opinion unsupported by studies. There are hundreds of thousands of studies on vaccines, including the harmful result of vaccines. Everything that goes into your body has risks, but you present your opinion as if vaccines are more dangerous that the alternative. Please support from a reliable source. The Enron comment is a straw man/red herring. Jul 8, 2018 at 5:20

I don't believe that there is an argument that vaccines are an overall net negative to public health. However, it does bother me that some folks try to sweep vaccine reactions under the rug as if they don't exist. It also bothers me when doctors who point out the risks are verbally tarred and feathered.

To me, when you consider any medical intervention, any medical intervention at all, there are always risks and side-effects. Even common drugs like aspirin that are widely regarded as safe may sometimes cause lethal reactions in a few patients. That is not to say that they are bad drugs.

To see the big picture, you have to look at the benefits of the therapy and compare them to the risks. Robert Sears has written about this in his "Vaccine Book". He has pointed out that he has concerns about the safety of vaccine ingredients. He also points out objectively how many cases of infectious disease have likely been prevented by vaccination. (I've noticed that most writing about vaccines, whether for or against, descend into personal attacks against people with whom the author disagrees. Robert Sears seems to be one of the few authors to present objective facts about personally attacking others)

I would like to add further that vaccines are quite different from one another in terms of the ingredients used and how they are made. Some contain live pathogens; some contain dead pathogens, some contain fragments of dead pathogens. Some contain trace amounts of toxic chemicals, such as aluminum, to enhance the body's immune response to the vaccine. In short, asking "Are vaccines safe?" is like asking "Are pain pills safe?" Each one has a different profile of risks and potential side effects.

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    And therein lies the problem... People generally have a poor grasp of risk and mistakenly believe that their choices are the right ones even if the data says otherwise. The likes of Robert Sears encourage (and profit heavily) from the idea that there is a debate or discussion to be had around vaccination when the numbers say there is a greater risk in travelling to or from the clinic... Apr 6, 2015 at 14:45
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    Just because Bob Sears writes like a nice guy doesn't mean that his claims have merit. He's not an immunologist, he's not an epidemiologist. He doesn't have the training to be drawing conclusions against the vast consensus of the AAP and the WHO.
    – swbarnes2
    Apr 6, 2015 at 16:26
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    @James, you are absolutely correct to say that people generally have a poor grasp of risk; consider the fear of flying, for example. I agree with the consensus that with few exceptions, vaccination is a net positive. However, I also believe that when we heap scorn on people who ask questions or express concerns, it's like pouring gasoline on a fire. Questions and concerns need to be addressed, not ignored. I would like to point out that staunch anti-vax people hate on Robert Sears with just as much vitriol as many staunch pro-vax people do. Why? He doesn't share their opinion exactly. Apr 9, 2015 at 14:34

Here are some arguments:

  1. The government created the vaccine injury compensation fund in 1988 to pay people injured by vaccines. Their site is here: http://www.hrsa.gov/vaccinecompensation/index.html
  2. In the 1970s pharmaceutical companies were being sued a lot for vaccine injury. These companies were going to stop producing vaccines but the government stepped in and made a law that makes it illegal for anyone to sue a pharmaceutical company for vaccine injury. More info here: http://www.cdc.gov/vaccinesafety/Vaccine_Monitoring/history.html

As a parent you have to decide what poses a greater risk to your child: the diseases or the immunization.

It may be against your religion, specifically Christianity and Judaism. Leviticus prohibits consuming 'diseased' meat. Vaccines are made by infecting animal or human fetal tissue and then extracting the virus from it. Every vaccine contains some infected tissue.

You may also object to aborted fetuses being used in this way. For some vaccines you can find a vaccine from a different manufacturer that uses animal tissue as opposed to aborted human fetal tissue.

Not one study has been done to investigate whether there are any negative effects associated with the complete vaccine schedule recommended by the CDC. Individual vaccines must be tested but they're not all tested together. A controlled study should be performed that compares vaccinated and unvaccinated children.

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    As a parent you should not be making decisions on medical harm just based on what you read online. You should also be consulting trained medical practitioners--which a vast majority will tell you what the science says: get your child vaccinated. The two bullets points are also not very useful arguments against immunization. They're likely very good arguments for total health care reform (taking power away from big pharma) but don't, in and of themselves, provide an argument for not vaccinating your child.
    – DA01
    May 26, 2012 at 16:35
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    Also, it's not just about what would cause greater risk to your child. It's also about what would cause a greater risk to your child...and their siblings...and their classmates...and their community.
    – DA01
    May 26, 2012 at 16:41
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    @Beofett the question is fine. It's asking for objective reasons against immunization. This answer does not contain objective reasons against immunization unless we count extreme and specious edge cases based on questionable correlations. We COULD count that, but, again, then nearly every question asked on the site could have these considered as useful answer when they really are not.
    – DA01
    May 27, 2012 at 17:32
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    The source given reads: "Legal decisions were made and damages awarded despite the lack of scientific evidence to support vaccine injury claims", so I don't think it answers the question the way it's being presented here. An attempt to prevent out-of-court settlements for nuisance suits from leading to epidemics is not evidence of serious harm, it's evidence of ambulance chasing. As Beofett points out, there is a good table there, but all it gives is an acknowledgement of potential harm, not actual figures.
    – deworde
    May 28, 2012 at 0:54
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    Not a useful answer. As noted by others, the creation of the VICF is not an objective argument against vaccinations, nor is the removal of liability from the pharmaceutical companies - since the fund was created to ensure that those who do experience the extremely rare serious adverse reaction could be compensated for it. It's a bit odd - claiming that removal of liability is a reason to not vaccinate, while also claiming that the fund set up to compensate families for not being able to sue the companies is also a reason to not vaccinate. That's rather circular...
    – Darwy
    May 28, 2012 at 11:17

My wife's brother and cousin both developed autism immediately after getting their MMR vaccine. They had a severe reaction that included fever and seizures and they were autistic afterwards. The medical community can state all day long that the vaccines did not cause this and we do not believe them. Watch the movie The Greater Good for more information about this.

It is believed that some people's bodies aren't able to deal with the mercury in the vaccines. We will not be giving our children any vaccines.

Vaccines were not responsible for the decline in diseases anyway: http://childhealthsafety.wordpress.com/graphs/


I should have left out the 'propaganda' stuff and just given a personal testimony. Oh well.

Ana, yes. Her brother was 18 months when this happened. He was talking. He got his MMR shot. That night he got the fever and seizures. That lasted two days. After this he stopped talking and eating and he wouldn't look at people any more. They stopped giving him vaccines. Her brother was fortunate and got much better. Today 11 years later you would just think he's odd. Her cousin was not fortunate. Today he is a 20-year old severely autistic young man. He still does not speak or look at you and his parents take care of him.

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    The general medical and scientific community is pretty clear that the mercury found in vaccines (few, if any, of which are part of standard childhood immunizations in the US) is unrelated to ASD. The idea that vaccines cause autism has been pretty thoroughly debunked. Claiming vaccines "do more harm than good" is dangerously wrong.
    – user420
    May 25, 2012 at 19:55
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    The movie 'The Greater Good' is propaganda, plain and simple. It does not have supporting science or studies behind it. Your final link is to a known anti-vaccination propaganda site, and the conclusion of 'vaccines were not responsible for the decline in diseases anyway' is also incorrect. None of those graphs present indicate the MORBIDITY of the diseases (their incidence), instead focusing on the mortality.
    – Darwy
    May 25, 2012 at 20:08
  • I'm very curious about the sudden development of autism (regardless of the cause). Did the kids point to objects before? Make eye contact? Cry when their parents left the room? Understand a few words, respond to commands like: "Bring me the ball"? I read that autism can be diagnosed only about 18 months into someone's life, but I find that strange as my kid was smiling and blabbering to toys with a face (eyes) already when he was three months old. He would also look directly into your eyes (not your hand) if you would suddenly grab his foot. Does all of this suddenly disappear with autism?
    – Ana
    May 26, 2012 at 7:29
  • Ana, I updated my answer. May 26, 2012 at 12:25
  • @Ana autism is a spectrum disorder. There's no 'one' symptom that defines it.
    – DA01
    May 26, 2012 at 16:39

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