Human foreskin in vaccines – another anti-vaccine zombie myth

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Many of us who write about vaccines point out the zombie myths of the anti-vaccine world. These are myths about vaccines that we successfully debunk, then a few months, even years later, they reappear on the scene. And numerous websites breathlessly report these myths as if they’re new news. The new old zombie myth is that somehow human foreskin ends up in your vaccine.

We will discuss how human foreskin is related to vaccines, and it is fairly interesting. But you can guess that the only reason this is a thing is because there is a huge intersection between the intactivists, those who oppose circumcision, and the anti-vaccine world.

We’re going to ignore the whole circumcision argument, even though there is a lot of scientific evidence supporting it as a medical procedure, as this article is solely about vaccines, or at least the use of human foreskin in developing and producing vaccines. And why human foreskin in vaccines is another zombie myth.

Why is human foreskin used with vaccines?

I am convinced that the anti-vaccine world thinks that scientists, in a lab in their garage, throw a bunch of ingredients, including human foreskin apparently, into a blender, chop it all up, and package it into a vial. In reality, vaccine manufacturing is incredibly complex, with the safety of patients at the center of each step.

Human foreskin is used in researching and developing, and possibly in manufacturing some future vaccines. Although most vaccines are produced using “immortal” cell lines, like HeLa, or limited cell lines, like WI-38, sometimes researchers need a primary cell line, like fibroblasts found in human foreskin.

Why are primary cell lines so important? Well, ass the methodical Orac describes, have to understand the difference between primary cells and cell lines. Primary cells are cells grown in culture after having been directly isolated from an organism. Human foreskin fibroblasts, isolated from—yes, and yuck—discarded foreskins from circumcisions, are commonly used primary cell lines. The advantages of primary cell lines is that they are more like “normal” than cell lines. The key disadvantage of them, however, is that they only replicated a limited number of times and therefore, as they are passaged in culture they undergo senescence and stop growing. Cell lines, on the other hand, can divide indefinitely.

For some viruses, it is important to use primary cells because the viruses themselves are so selective that they only thrive on those cells, because, as Orac says, they are more “normal.” Sure, there may be other sources of human fibroblasts, but human foreskin happens to be a large, easily isolated, source of the cells.

Does the human foreskin DNA contaminate the vaccine?

Again, back to my metaphor that vaccines are apparently manufactured in blenders – if you realize that vaccine manufacturing is a lot more complicated, then you’ll realize that this myth is silly. As Orac states,

So what about DNA contamination? I’ve discussed in detail why it’s incredibly unlikely that any vaccine would contain sufficient DNA from the cells in which its virus was grown to have a significant effect on the organism to which the vaccine is administered…

Manufacturing of vaccines is incredibly complex, where there are several steps that remove impurities, including DNA that doesn’t belong there.

Even if there are some fragments of DNA that get through the purification process, so what? That DNA isn’t suddenly going to incorporate into the vaccinated patient’s genome and proliferate through the whole body. This is one of the anti-GMO arguments that I have debunked in the past:

If gene transfer were so simple, the medical usefulness of gene therapy would be extremely high, instead of being incredibly difficult, if not impossible. We’re trying to transfer genes to cure diseases, and researchers have not shown a lot of consistent success. If consuming a few kernels of corn, introduced some gene into the bloodstream that somehow gets incorporated into the human genome, well that would be a miracle. But reality is, even if the article is accurate, and there’s doubt to that, it has little clinical meaning.

So, let’s sum up all this science. There isn’t a lot of evidence that supports the belief that there is a lot of DNA contaminating the vaccine. And there is even less evidence that if there is contaminating DNA it can actually do any harm to the patient. In other words, this is biologically implausible, if not impossible.

There’s one more point. As far as I can tell (and I always am open for correction), foreskin fibroblasts are not used in the production of any vaccine at this time. They were used in research to isolate the human papillomavirus (HPV), which, of course, was necessary for the manufacture of the HPV vaccine. These fibroblasts also were used in testing the HPV vaccine, but of course, that does not mean it’s been used in manufacturing.

Foreskin fibroblasts have been also used in research on the Varicella zoster virus (chickenpox), but there is no evidence that it has been used in developing or manufacturing the chickenpox vaccine.

There seems to be some research into using these fibroblasts in some future vaccines, such as a cytomegalovirus vaccine, but again, nothing for current vaccines. Once again, if it were, almost none of the DNA from the fibroblasts will end up in the vaccine, and even if it did, that means nothing to the patient.

Where do these vaccine researchers get the human foreskin?

Mostly, these researchers buy the tissue from companies that isolate and package various cell lines. This saves time for researchers, who don’t have to obtain tissue and then isolate the cell lines. When I was in grad school, I used to stand outside of the delivery room at the medical school to get human placenta which contained a high concentration of a particular cell receptor that I needed for a research study. It took several days to isolate the cells that I needed from the placenta, time I could have spent on doing other work.

The companies often purchase the tissue from hospitals. So, this part of the myth is correct – it is entirely possible that babies’ foreskin is sold after a circumcision. However, this is done only with the permission of the parents.

And no, patients are generally not compensated for the donation of tissue or organs. The reason for this is pretty easy to explain – if individuals were allowed to sell organs from themselves or from relatives, it would be highly disruptive to the whole transplantation system. For example, a recently deceased patient’s family could offer a liver or heart up for bidding, meaning the wealthiest patients, not the neediest, would get access to organs. In fact, even hospitals cannot sell organs. On the other hand, tissues generally aren’t used to directly save lives, so selling them isn’t considered unethical.

Human foreskin and vaccines – the summary

This old zombie myth has been reanimated once again, and I will try to play Rick Grimes to put it down. Yes, human foreskin cells are occasionally used in researching and developing old and new vaccines. There are very good reasons for doing this, including the viability of these cells in producing the viruses.

And of course, tissues are occasionally sold by hospitals to companies that isolate cells for use in research. This is only done with patient permission, so it’s not unethical or immoral. It is how research is done.

Finally, as far as I can tell, no current vaccines use foreskin fibroblasts for production. Even if it did, there is little chance of significant amounts foreskin DNA ending up in the final vaccine. And even if that happened, there is almost no chance that that DNA would have any impact on the patient.

It’s clear that this myth is cynically used by the anti-vaccine movement to scare parents, especially those who might have concerns about circumcision. The myth has nothing to do with the safety and effectiveness of the vaccines – in fact, using these fibroblasts are important to creating safe and effective vaccines.

The anti-vaccine radicals are uninterested in real science just creating strawmen to scare people.


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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!