Does anyone have any experience with severe reactions to vaccinations and how to proceed? My 2 month old had a severe reaction to his first round of standard vaccinations.

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    What qualifies as severe? Jan 26, 2012 at 1:41
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    If you suspect it's severe, call the doctor. A fever, loss of appetite, and being tired are common side-effects. Call the doctor just to put your mind at ease. Most of the time vaccinations do not cause reactions that require any intervention.
    – user808
    Jan 26, 2012 at 20:20
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    This is medical advice, IMO, and is off topic. The answer is always: Call a doctor. Jan 26, 2012 at 23:14
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    In case you start getting all sorts of "helpful advice" from anti-vax folks, I suggest: factsnotfantasy.com/vaccines.php as a helpful counter to many of the myths surrounding vaccines.
    – JasonR
    Feb 3, 2012 at 13:45

3 Answers 3


According to the CDC, you should look for...

any unusual condition, such as a high fever, weakness, or behavior changes. Signs of a serious allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat or dizziness.

If that's what you're seeing, I hope you called a doctor right after posting your question. If not, do so now. If it's not severe, keep an eye on him and call your pediatrician if it persists. Things like mild soreness, fussiness, or redness at the injection site aren't usually a concern except for being uncomfortable for him.

  • Note that mild fever is a normal reaction (the immune system is "processing" the vaccine information). High fever is above 100.4 F (38.0 C) in small children, 103 F (39.4 C) for adults. At these temperatures and above, seek immediate medical help.
    – Mindwin
    Oct 2, 2014 at 13:36

In addition to Karl's point, most people have a reaction to vaccines. It is just more worrying when it is a child as it can be so difficult to gauge seriousness.

Common reactions, as j.rightly said, include fever, loss of appetite, and being tired.

If anything else happens, call the doctor - but also, call them if you are worried at all by anything out of the ordinary.

Especially if this is your first child it can just be very tricky to know what is serious, so take the safer route.


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.

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 and do more harm than good: http://childhealthsafety.wordpress.com/graphs/

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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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    Thimerosal (ethyl mercury) has been removed from nearly all childhood vaccinations used in developed nations. With the exception of trace amounts (less than 3 ug) or the flu vaccine, there is NO MERCURY IN VACCINES. 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 20:09
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    "We will not be giving our children any vaccines" that's putting your kid's, and everyone else's kids at extreme risk for some very nasty diseases.
    – DA01
    May 25, 2012 at 21:56
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    I want to downvote this answer for its general ignorance and social irresponsibility (ie, putting immuno-compromised kids at risk because the poster does not understand the science), but I don't want this post to disappear due to massive numbers of downvotes. People who don't vaccinate are putting their own and other kids at risk; those who don't believe or understand this should start looking at Herd Immunity (en.wikipedia.org/wiki/Herd_immunity)
    – mmr
    May 26, 2012 at 1:05
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    Plus, I would never wish polio on anyone, especially just because their parents don't understand the threat. I've known people who got polio just before the vaccine came out, and the disease was utterly devastating to them and their families.
    – mmr
    May 26, 2012 at 1:07

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