Multiple vaccines overwhelm immune system – another myth debunked

There are a large number of tropes and myths pushed by the anti-vaccine crowd. Like toxic chemicals in vaccines. Or vaccines cause autism. And one that keeps showing up – multiple vaccines overwhelm the immune system.

And like other articles I’ve written about anti-vaccine myths and tropes, the idea of multiple vaccines harming children is easily debunked by scientific facts. And we’re doing that right here.

Multiple vaccines harm the immune system – the myth

multiple vaccines
Another meme about multiple vaccines, because if you don’t have science, create a meme.

The basis of this myth is that there are a lot of vaccinations. The meme above is one that pushed by a lot of vaccine denialists that the number of vaccines has increased over the years, and yes it has. The CDC vaccine schedule is somewhat different (pdf), which shows 37-38 (depending on how the flu seasons overlap with child’s age).

There are even some anti-vaccine activists who use larger numbers for vaccines by counting the number of antigens in each vaccine. For these people, a quadrivalent flu vaccine counts as four shots.

One of the big proponents of the alternative vaccination is schedule is Dr. Bob Sears, who pushes the myth is that there are too many vaccinations. And tries to sell a lot of nonsense on his website, but that’s a different story. The meme to the left is one that promoted by a lot of vaccine deniers (or again, vaccine delayers) that the number of vaccines has increased over the years. And, yes it has, partially because we have a lot of new vaccines since the 1980’s, but also, we have more scientific evidence that has fine-tuned the vaccine schedule to prevent diseases that can harm.

From this “multiple vaccines harm children” myth, it branches into a lot of sub-myths. One is that there because of all of the scary toxins in the vaccines, and the kids are getting more of them with all of the scary vaccines. I dealt with that issue, and it’s not an issue.

But the bigger sub myth is that somehow multiple vaccines damage the immune system, because “that’s too many antigens for the young child’s immune system.” They make claims that these excess vaccines “use up” the immune system (yes, use up). Or that because vaccines aren’t natural, they mess up the immune system.

This trope about the immune system contradicts what we know about it. If I could make just one scientific claim, it’s that the immune system, even of children, is powerful, robust, and complex. Our immune system is the result of a hundred million years of mammalian evolution, and millions of years of human evolution,  which has protected our species from billions of different bacteria and viruses.

Multiple vaccines harm the immune system – the science

If you’re worried about too many vaccines, here’s what the experts say:

  • Do Children Get Too Many Immunizations? The Answer is No, Mark Crislip–”Delaying vaccines increases the time during which children are susceptible to certain diseases, some of which are still fairly common. Chickenpox, whooping cough, influenza, and pneumococcus still cause hospitalizations and deaths in previously healthy children. Spacing out or separating vaccines will also require more doctor visits, which will increase overall costs as well as the number of times the children must experience any associated discomfort and stress.”
  • The Problem With Dr Bob’s Alternative Vaccine SchedulePaul A. Offit, MD Charlotte A. Moser, BS–”At the heart of the problem with Sears’ schedules is the fact that, at the very least, they will increase the time during which children are susceptible to vaccine-preventable diseases. If more parents insist on Sears’ vaccine schedules, then fewer children will be protected, with the inevitable consequence of continued or worsening outbreaks of vaccine-preventable diseases. In an effort to protect children from harm, Sears’ book will likely put more in harm’s way.”
  • Alternative Vaccination Schedules, Mark Crislip (Science Based Medicine)–”The preponderance of information in the medical literature on vaccinations is as clear as any topic in medicine.  Vaccines are effective and they are safe.  The best bet for keeping your child, and your community, healthy is to get vaccinated and to do it on schedule.  There are people who see the issue differently, and is often the case, the reasons are more subtle and complicated that one would except.  And there is still much to be understood as to why people do and do not participate in the vaccination schedule.”

Let’s take a look at what actually happens in the real world with children’s immune systems. In this paper, researchers discovered that:

  • In each cubic meter of air, there are between 1.6 million and 40 million viruses.
  • In each cubic meter of air, there are between 860,000 and 11 million bacteria.

A child inhales about 5 liters of air per minute (or about .005 cubic meters), so a few hundred thousand viruses and bacteria are inhaled every minute every day of the year by an infant. And the researchers discovered that many were unknown species of viruses and bacteria, so the immune system has to adapt to them with each breath.

Thus, the 35-40 antigens from vaccines is not even a significant number compared to the millions upon millions of viral and bacterial antigens that enter a child’s lungs every day or week. The tiny number of antigens introduced by vaccines barely register on the immune system’s massive and robust power to deal with antigens.

The anti-vaccine gang fail to realize the incredible power of the immune system. It “memorizes” literally billions, if not a 1000 times more, of antigens. The handful of antigens introduced by vaccines are critical because those antigens are from dangerous pathogens – the immune system just adds that information about these pathogens into its memory bank, it doesn’t get overwhelmed by it.

The complicated and powerful immune system doesn’t get weakened by the “knowledge” from the vaccines. It just moves on to the next antigen, one of the few million that it sees every day. The immune system does not get weaker, unless you have chronic diseases or malnutrition. You can’t make it stronger, but vaccines cause it to adapt to that particular antigen, so that it “remembers” what to do the next time it encounters that antigen.


This is easy. Vaccines simply cause the development of adaptive immunity to a pathogen or antigen. This is something that happens a millions of times a day in a healthy child, teenager, and adult. If the vaccine denialists could bring one tiny bit of evidence that vaccines did something different than cause that adaptive immunity, then we could talk. But they can’t.

As Paul Offit summarized in his landmark paper about multiple vaccines::

Current studies do not support the hypothesis that multiple vaccines overwhelm, weaken, or “use up” the immune system. On the contrary, young infants have an enormous capacity to respond to multiple vaccines, as well as to the many other challenges present in the environment. By providing protection against a number of bacterial and viral pathogens, vaccines prevent the “weakening” of the immune system and consequent secondary bacterial infections occasionally caused by natural infection.

So more evidence that vaccines do not do what vaccine deniers claim they do. And they do precisely what scientists think they do–save lives.

So, do multiple vaccinations overwhelm the immune system? That’s definitely a myth unsupported by real science.




The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!