Skeptical Raptor's Blog hunting pseudoscience in the internet jungle

Polio vaccine does not cause cancer–debunking a myth


For New Year’s Day, I’m republishing the top 10 articles I wrote in 2013. Well, actually top 9, plus 1 from 2012 that just keeps going.

#7. This article was published on 23 July 2013, and has had over 6000 views. Polio vaccines do not cause cancer. Ugh.


This article has been substantially updated with more information. Please check it out.


The interesting thing about social media (Facebook, Twitter, blogs, Google, reddit) is that it’s fairly difficult to thoroughly and completely debunk pseudoscientific myths. The first problem is that individuals choose to accept a meme or a Tweet as factual without using any critical thinking skills (for example, not even clicking on the link to the original article to determine the veracity of it). The second problem is that social media fallacies have multiple lives, so when someone reads one of these memes a year from now, they think “yeah, this is great information”, and pass it along as if it’s the Truth. Which means we skeptics have to debunk it again and again and once more, again.

I wrote an article a while ago about some nonsense meme on Facebook that contended that eating ripe bananas cured cancer because the bananas contained a protein called tumor necrosis factor (TNF). It was based on some “Japanese scientific study,” which took significant effort to find. After a critical and thorough reading of the article, I concluded that: the study made no claim that bananas made TNF, AND even if bananas did, you couldn’t ingest enough bananas to get a bioactive dose of TNF, AND even if you could, you wouldn’t absorb any TNF through the digestive tract, AND TNF doesn’t do what the meme writer thought it does (TNF is badly named, and does not directly attack cancers). In other words, it lack any truth, except, maybe that bananas are yellow. Amusingly, I can tell when the banana myth blows up on the internet, because suddenly my article on TNF and bananas gets thousands of hits over a week as people search out a critique (or I suppose support) of the meme. I originally wrote the article early in 2012 (I’ve updated it a couple of times, to clear up language and to add more information), and it has gone through at least 6-7 cycles of tens of thousands of Google hits, then going quiet again for a few weeks, sometimes just a few days.  It was not my intention, but that article has remained the most-read article I’ve ever written.

Thus, the best we skeptics can do is keep debunking these social media fables and tall tales, and move along to refuting the next one in line. At least I can save time by not having to write the article again, we can just update with any new information and re-debunk (yes, I have the absolute right to invent words).

Recently, I ran across two presumably “breaking news” (scare quotes intentional) articles that gave the impression that someone has uncovered the fact that polio vaccines cause cancer. Now, I tend to take notice when “cancer” and “vaccines” intersect in the blogging world, mostly because I assume that the article will be about Gardasil and HPV related cancers. In these cases, I was wrong.

The articles, CDC Admits 98 Million Americans Received Polio Vaccine In An 8-Year Span When It Was Contaminated With Cancer Virus and CDC Admits 98 Million Americans Received Polio Vaccine Contaminated With Cancer Virus. The former of those two articles is authored by Dave Mihalovic, is a naturopathic doctor (typically someone who eschews science-based medicine in favor of pseudoscience like homeopathy and acupuncture), who claims to be a “vaccine researcher.” If he’s a vaccine researcher, he has published exactly zero indexed articles about vaccines, or any other field of real medicine. In other words, his research probably means he spent a few hours on Google and thinks he’s now as smart as anyone who actually has a bachelor’s and doctoral degree in immunology, virology, biochemistry or some other biomedical science along with a decade or two research in a world class laboratory. Mihalovic is as much a vaccine researcher as I am an Oscar winning screenwriter. I can say that I write screenplays. I can claim that I am Steven Spielberg’s best buddy. But it would take you about 14 nanoseconds to find that there is no evidence of my being a screenwriter, and you’d just think I was nuts. Mihalovic, of course, thinks he’s as brilliant as a real scientific researcher, but like my credibility as a screen writer, he has approximately no credibility as a “vaccine researcher.”

Nevertheless, let’s get back to what these vaccine deniers are claiming:

  • Polio vaccines were contaminated with the SV40 virus (known as simian virus 40, a polyomavirus that is found in both monkeys and humans),
  • SV40 causes cancer,
  • And, the CDC admits that 98 million Americans are at significant risk of SV40 infection and thus cancer.

I would be frightened by these articles if I weren’t a scientific skeptic and didn’t utilize my critical thinking skills. Because of those three statements, none, with the partial exception of the first one, are supported by evidence and high quality science. Here’s story, based on scientific and historical information, available to anyone with the ability to critically analyze a story:

  • The groundbreaking and lifesaving polio vaccines, developed by Jonas Salk (injected, inactivated virus, vaccine) and Albert Sabin (oral, live virus, vaccine) in the early 1950’s, and were produced using VERO green monkey kidney cell lines. Typically, viruses used in vaccines need to be “grown” in a cell line, because viruses cannot replicate themselves without hijacking an infected cell. You just can’t grab a handful of virus and will it to reproduce and multiply.
  • In 1959, microbiologist Maurice Hilleman found a monkey virus in both vaccines—it was the 40th simian virus tone discovered by scientists, hence the SV40 moniker. Back in the 1950’s, we didn’t have the technology that we do now to screen for contaminants, so the SV40 virus had contaminated the VERO line well before production of vaccines. Not all of the cells in culture were contaminated, just some of them.
  • Salk’s inactivated virus vaccine, which was treated with formaldehyde (only a tiny amount remains in the vaccine), had very small amounts of the virus. On the other hand, Sabin’s live oral vaccine was heavily contaminated with SV40.
  • Worried about the potential effects the virus could have on humans, researchers injected it into hamsters, finding that nearly all of them developed massive cancerous tumors. But, as I’ve said on numerous occasions, primary research should be examined carefully before accepting that it has any type of applicability to human health.
  • Upon further review of the initial studies, it was observed hamsters that ingested SV40 instead of being injected with it didn’t develop any cancers. In other words, Sabin’s live oral vaccine (which actually had a higher burden of SV40 than the injected, inactivated virus Salk vaccine) did not cause any cancer. Additional studies showed that children who were given Sabin’s vaccine did not develop antibodies to SV40; apparently, the virus quickly and safely passed through the child’s digestive system, never causing an SV40 infection.
  • On the other hand, Salk’s vaccine, which contained very little SV40, but was given by injection, and there was evidence that some of these children might have been infected with SV40. However, recent studies have shown no credible evidence (here, here, here and here) that those children who received SV40 contaminated vaccines had an increased incidence of cancer as unvaccinated children. No plausible evidence suggests that SV40 has ever caused cancer in humans.
  • And polio vaccines have been SV40 free since 1963 in most advanced countries, although Soviet bloc vaccines were contaminated until the 1980’s.

Predictably, the information spread by the “polio causes cancer” articles pushed by the vaccine deniers are wrong on so many levels. First, not all polio vaccines were contaminated, and the SV40 virus in the oral vaccine merely passes through the digestive tract without causing an infection. SV40, as shown in so many published articles, does not cause cancer in humans. If it does, it’s at such a low rate that it’s impossible to detect unless we check tens of millions of patients. Finally, the number of “98 million” is an incredible scary, but ultimately inaccurate number (a tactic employed the antivaccination crowd whenever it suits their needs to establish dangers of vaccines). The facts are before the SV40 virus was removed from the vaccine, around 98 million children got one of the two forms of the polio vaccine. However, eliminating those who got the oral vaccine, which, as we have established, did not infect children with the SV40 virus, approximately 10-30 million Americans were immunized with the Salk vaccine that contained the SV40. Potentially, only those 10-30 million Americans are at actual risk of contracting the SV40 virus; however, given the low levels (very low levels) of actual SV40 contamination of the vaccines, those numbers probably vastly overstate the SV40 risk.

What can we conclude? First, and most importantly, if you don’t believe anything about SV40 and cancer, those who received the vaccine after 1963 have no worries. There was no SV40 after that date, so if you’re under 50, you’re thinking “why did I read this story then?” And those over 50, there is no increased risk of cancer from SV40 contamination, so you also can say “why did I read this story then?” Well, I only investigated it because I was curious about what constituted evidence.

The problem with the lying liars who lie in the antivaccination movement is that if you just looked at the headlines for those articles, you’re probably terribly concerned that giving the polio vaccine to your children puts them at risk of cancers. Except the worry was eliminated 50 years ago. And there is no evidence that SV40 is causally linked to any cancer.

Polio vaccines have saved and will save many many lives. And we have irrefutable evidence for it.


Use the Science-based Vaccine Search Engine.


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