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Home » Debunking RFK Jr and Brian Hooker’s book “Vax-Unvax” – Part 3

Debunking RFK Jr and Brian Hooker’s book “Vax-Unvax” – Part 3


Last updated on April 23rd, 2024 at 11:38 am

This article, part 3 of a series of 4 debunkings of a new book, “Vax-Unvax: Let the Science Speak” is written by Frank Han, M.D., an academic board-certified pediatrician/ pediatric cardiologist. He splits his time between cardiac imaging (Nuclear, CT, MRI, and echocardiography), inpatient cardiology, and outpatient cardiology. He primarily cares for cardiology patients of all ages with congenital heart disease and is dedicated to educating pediatric residents and medical students.

Dr. Han first became aware of and interested in the incursion of pseudoscience into his chosen profession while completing his pediatric residency at Connecticut Children’s Medical Center and saw it explode during the COVID pandemic. He has since focused his efforts on spreading the joy of science literacy and teaching patients how to take charge of their health while navigating the tricky online world of medical information. Dr. Han has no conflicts of interest to disclose and no ties to the pharmaceutical industry. He can be found on Twitter as @Han_francis. The comments expressed by Dr. Han are his own and do not necessarily represent the views or opinions of OSF Medical Center, or the University of Illinois College of Medicine.

As I did in Part 1 and Part 2 of this series, I will focus on one chapter of the book “Vax-Unvax: Let the Science Speak,” by Robert F Kennedy Jr and Brian Hooker. Part 3 will focus on thimerosal.

vax-unvax mercury

Debunking Vax-Unvax – all about thimerosal

The debunking of Chapter 3 is easy – they are complaining that thiomersal (most of the world spells it thiomersal, but in the US it is thimerosal), a vaccine preservative, is responsible for many perceived vaccine-related adverse events and side effects.

The ingredient was originally added to protect against fungal infections. Early in vaccine development, people were killed by vaccines with insufficient preservatives and contaminated with bacteria (specifically an early iteration of the diphtheria vaccine). The central refutation to their point is – the US, UK, and Europe moved to remove thiomersal from all vaccines except the multi-dose influenza vaccine even in the absence of clear evidence that thiomersal specifically was causing any consistent harm beyond allergic reactions.

So, one can conclude that the authors of the book have an impaired understanding of basic historical events. Thiomersal was never shown to have caused any autism in amounts present in vaccines, and it can’t cause any problems now – because it has been removed. Even with the influenza vaccine, the end user can request a preservative-free vaccine.

Debunking “Vax-Unvax” — thiomersal and vaccines

The story of thiomersal goes back to the search for a safe and effective preservative for some of the early iterations of vaccines (it reaches back to the 1930s). Logically, vaccine manufacturers and end-users alike don’t want mold or bacteria to grow in their vaccines before they reach the arm of a patient, and so in the search for a safe and effective preservative, thiomersal was studied and used in early childhood vaccines.

As time passed there were concerns about the toxicity of mercury and its relationship with autism, but the people generally expressing these concerns have a poor command of the biochemistry behind thiomersal.

There is mercury metal, ethylmercury, and methylmercury, which are the three versions of mercury relevant to this discussion. When the thiomersal molecule reaches the body, it is broken down into two molecules, one of which is ethylmercury, which through the normal metabolic processes of the body, is eliminated.

Methylmercury is generally a product of bacterial interactions with the metallic mercury atom, and this form is stored in the body for much longer and is part of the reason why there are intake limitation recommendations on tuna, which can accumulate methylmercury.

Mercury metal looks nice in thermometers, but hopefully is not something that everyday people are exposed to, as this has well-established toxicities. The key point here is that thiomersal, in the concentrations present in vaccines, did not have consistent evidence demonstrating that it was a genuine threat to health and safety. The preservative was removed anyway as a precaution.

The corollary argument given by dedicated antivaxxers is that thiomersal is related to autism. If that were true (which it is not), removal of thiomersal should have caused a decrease in total yearly autism diagnoses. The actual number of diagnoses has risen, due to multiple reasons.

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