Dear Anti-​​Vaxxers: Don’t Draw Parallels Between Vaccinations and Thalidomide, It’s Just Plain Uninformed

A completely ridiculous phenomenon I have noticed by anti-​​vaxxers is the drawing of parallels between vaccinations and the thalidomide disaster. While it’s rare, it does happen, so it’s worth writing about.

Rachael Dunlop mentioned the following on episode 112 of The Skeptic Zone, in relation to “a seminar from paediatric chiropractor Nimrod Weiner, entitled Vaccinations: Make an Informed Decision”:

We were also reminded that although scientists say that vaccines are safe, they also said the same thing about asbestos, cigarettes, and thalidomide.

This was further blogged about on The Sceptics’ Book of Pooh-​​Pooh blog.

Now, this may not have a truly skeptical bent, but I describe what thalidomide is, the catastrophe it caused, and why a similar medical tragedy will not happen again. That is to say, why drug regulation has since changed to avoid another disaster. And thus, why vaccination needs not be compared to thalidomide.

I’m going to use an extract of a blog entry by James Randi as the tl;dr version of this article for those who want to stop reading now:

When the thalidomide scare erupted in the 1950’s, the public’s fear of medical science was brought to a peak. That drug was withdrawn when it became known that birth defects could be a side-​​effect of its use, and though it is still used with a different application, that dreadful lesson is still before us. We’ve learned a lot since then, as we tend to do when errors are made, but the idea that vaccines cause autism is a very thoroughly tested, researched, and disproved notion.


Frances Oldham Kelsey

Frances Oldham Kelsey

Thalidomide was discovered/​invented by Chemie Grünenthal, a German pharmaceutical company, in the 1950s (for context, this was after World War II). It was marketed under a number of different names; notably Contergan in Germany, and Distaval in the UK and Australia. Thalidomide didn’t make it into the market in the United States, as Frances Oldham Kelsey of the Food and Drug Administration (FDA) was unconvinced of the safety of the drug, asserting that further testing was required before the drug could be distributed. For this, she was later awarded the President’s Award for Distinguished Federal Civilian Service. In Germany, however, thalidomide was widely used:

By 1961, thalidomide was the best-​​selling sedative in Germany, with total sales of DM 12.4 million, five times as much as its leading competitor, Doriden. Thalidomide sales soon represented half of Grünenthal’s total income, and by this time many of the company executives’ personal incomes were tied to its sales. The growth of the company was dramatic: in 1954, when the drug was formulated, Chemie Grünenthal had 420 employees; by 1961 the company employed more than 1,300. This was mostly because of the remarkable success of thalidomide (Brynner & Stephens, 2001, p. 15).

As for the UK and the rest of the world…

So without conducting any trials of their own, in April 1958 Distillers began distributing Distaval, their nearly eponymous trade name for thalidomide, throughout Britain. It was advertised as “completely safe,” the solution to the “mounting toll of barbiturate deaths.” Before long thalidomide was outselling its main competitor three to one. Distillers’ market included the British Isles, Canada, Australia, and New Zealand. Eventually thalidomide was distributed in forty-​​six countries throughout Europe, Scandinavia, Asia, Africa, and the Americas. During the peak year of 1961, 25 percent of thalidomide sales were in these foreign countries (Brynner & Stephens, 2001, p. 16).

But was was thalidomide exactly? It was a “cure-​​all”. It was used as a sleeping aid/​sedative/​hypnotic, that was viewed as safe and effective. Thalidomide was thought to be a safe alternative to barbiturates such as phenobarbital — while barbiturates can be deadly, no acute toxicity (harmful effects from a single use) was found for thalidomide. No prescription was needed, no deaths were recorded from overdose, and even taking a whole bottle of the drug would only have the short-​​term effect of sleep. Further, and very importantly in the story of thalidomide, it was used to prevent morning sickness in pregnant women. It was not yet known that drugs could cross the placenta and harm developing babies.

Thalidomide child

But. Thalidomide was doing a lot of harm due to its chronic toxicity (harmful effects from repeated exposure). Continual use of thalidomide led to neurological problems, reports of which began to surface from clinicians in the late 1950s and early 1960s. Continual use of thalidomide led to peripheral neuropathy, a death of nerves in the periphery that leads to a permanent numbness and tingling sensation in the hands and feet. Initial speculations about a connection between thalidomide and neuropathy were published in the British Medical Journal in the early 1960s. For instance, A. Leslie Florence reported a personal observation of a correlation between patients regularly taking Distaval and experience of paraesthesia, coldness of extremities, and other problems. She also noted that when patients stopped taking the drug, there was a decrease in expression of symptoms.

Notably, thalidomide caused severe birth defects in children whose mothers had taken the drug during the 35th-​​49th days of pregnancy (recorded by Widukind Lenz). Thalidomide caused phocomelia, or flipper-​​like arms. It also caused thumbs with three joints, defects of bones in the legs, and even complete absence of arms. The majority of “thalidomide children” died before their first birthday. William McBride discovered, and announced to the world, via The Lancet in 1961, the teratogenic (causing birth defects) effects of thalidomide. He later set up a foundation for research into birth defects, and has been awarded a CBE and AO.

In 1961, thalidomide was withdrawn, however the drug was truly pernicious, harming tens of thousands of people worldwide (Brynner & Stephens, 2001).

Drug development after thalidomide

Distaval advertisement

Advertisement for Distaval, asserting safety and suitability for children

The thalidomide tragedy led to now-​​stringent drug-​​development processes. Frances Oldham Kelsey knew thalidomide needed to be tested further before it could be marketed in the US, but generally drugs could be approved without proof they were efficacious. At present, there is more rigour involved in drug development, approval, and regulation.

There are a number of stages of drug development. The entire process commonly takes up to ten years, costing hundreds of millions of dollars, and “the enormity of the undertaking owes in great part to what was learned from the thalidomide experience” (Brynner & Stephens, 2001, p. 139). First, drug candidates must be discovered, whether via natural sources, or created synthetically. Before human clinical testing can begin, there must be evidence for safety and efficacy of the drug in animal testing. It must be shown that the drug will be efficacious and safe in humans. The first stage of clinical testing in humans uses only a small number of participants, and must demonstrate safety in conservative doses of the drug. The pharmacokinetic behaviour of the drug need also be established. This entails looking absorption, distribution, metabolism, and excretion (ADME) of the drug. Once safety at various doses has been demonstrated, the drug can be tested on participants who have the condition the drug aims to treat. Trials are placebo-​​controlled, randomised, and double-​​blind.

Drugs that have been successful in all stages, with safety and efficacy clearly established, can be submitted for approval. As already mentioned, in the days of thalidomide drugs did not even have to have an effect in humans to be approved, and there was no strict hierarchy of development stages (now there is; each stage of development must be successful before moving to the next). In addition, it was acceptable to make extraordinary claims about drugs, such as saying they had no side effects (all drugs have side effects). Now, a regulatory authority must evaluate the clinical data. In Australia, this is the Therapeutic Goods Administration. In the US, it is the Food and Drug Administration (remember this is where Frances Oldham Kelsey worked). The authority’s chemists, pharmacologists, and statisticians will evaluate all the data from clinical trials. They will then give approval or nonapproval along with a justification (Brynner & Stephens, 2001). Post-​​marketing surveillance occurs after the drug has been approved, in order to ensure safety.

Back to the anti-​​vaxxers

Unfortunately, there are people who compare vaccination to thalidomide, or compare western medicine in general to the safety (or lack thereof) of thalidomide, making comments about how we should not blindly trust modern western medicine. The quotation provided by Dr Rachie, earlier, is one example…

We were also reminded that although scientists say that vaccines are safe, they also said the same thing about asbestos, cigarettes, and thalidomide.

…but there are others around the Internet, if you care to search. Maybe it’s rare for anti-​​vaxxers to actually cite thalidomide as an example when promoting their nonsense, but it is one of the more ridiculous things you can do. Meryl Dorey and the The Australian Vaccination Network (AVN) aren’t averse to doing it:

Meryl DoreyWestern medicine’s record has never been good. Therapies which one year are touted as the safest and most effective around, are later shown to be dangerous and ineffective and quietly withdrawn. Just a few examples are Thalidomide for morning sickness, Relenza for Diabetes, cigarettes for the treatment of Asthma, Hormone Replacement Therapy for the symptoms of Menopause, Rotavirus Vaccine for the prevention of Rotavirus.

However, it need be noted that in the case of thalidomide, the withdrawal wasn’t quiet, and it is widely touted as “one of the biggest medical tragedies of modern times”. Ignoring other ridiculous claims of the AVN, another article on the website, containing letters that were sent to television program Sunday Night by uninformed parents, after the program’s “unbalanced” (any of the AVN’s supposed balanced reporting could only be called false balance) story about vaccination and the death of Dana McCaffery:

Many drugs are taken off the market because they are harmful after being approved for use, eg Thalidomide, and more recently Baycol, Pondimin, Seldane, Duract, Raxar, Lotronex, Hismanal, Posicor, Vioxx and the Rotavirus vaccine.

Now, Vioxx is something I feel warrants a brief mention in this entry, as it pertains to the question of whether another thalidomide could happen again. The drug rofecoxib (brand name Vioxx) was an anti-​​inflammatory used in arthritis patients, and was approved for use in 1999. However, the drug was later found to be associated with serious cardiovascular problems:

…a long-​​term clinical trial showed that some patients, after taking the drug for 18 months, developed serious cardiovascular problems. The data that ultimately persuaded the company to withdraw the drug indicated 15 cases of heart attack, stroke or blood clots per thousand people each year over three years, compared with 7.5 such events per thousand patients taking a placebo.

For this, the drug was taken off the market. The danger of rofecoxib was found through post-​​marketing surveillance (see previous section). Because of this stage of drug development, the extent of the damage was diminished. Without such safeguards, as in the case of thalidomide, catastrophes may result.

Conclusion and afterword

In the days of thalidomide, it wasn’t known that drugs could cross the placenta, and thalidomide did a lot of damage. But because of this, the drug development process is now extremely stringent. It is unlikely a similar medical catastrophe will happen again, and vaccination is certainly not to be compared to the thalidomide tragedy. I’ve just realised I’m preaching to the converted, so I won’t labour any points about the outlandish claims of anti-​​vaccination movement in regards to the safety of vaccines. Mainly, I just hope this article was an interesting read about the ridiculous practice of making parallels between vaccines and thalidomide.

The thalidomide story is fascinating, and there is a lot more to be said of it, such as and how and why it was eventually revived as an important medicine (with heavy safeguards in place, of course), but I probably already went too far out of the scope of this blog?

Importantly, I must also give a special mention to Michael Lew and Tony Hughes from The University of Melbourne Department of Pharmacology for teaching me most of what I needed to know to write this article.

If you have noticed any errors or inaccuracies, you can leave a comment, since I like being right.

Print references

Brynner, R. & Stephens, T. (2001). Dark remedy: The impact of thalidomide and its revival as a vital medicine. New York: Basic Books.