Tdap vaccine is not linked to autism, just like any other vaccine (including the flu vaccine)

I remember when my dad told me that there was no such thing as Santa Claus. He sat me down and told me that it had been him all these years who had been buying me gifts and placing them under the tree. It was quite a shock to have this revealed to me; it shook my world. I did everything in my power to reason it through. In my head, dad was a liar. Dad wanted to take the credit for the big jolly guy who’d given me all the gifts I’d ask for in the letters I sent him through my dad.

I was 27 years old.

Soon enough, I came to accept the truth. All the evidence was there in the form of my dad’s receipts for the gifts he had gotten me. People had seen him buy me those gifts. Mom swore to having helped him wrap them. The evidence was compelling, substantial, tangible, credible… Santa Claus was no more.

I’m sad to say that this is not the case with the anti-vaccine crowd. You can tell them all you want that vaccines do not cause autism, and that vaccines actually protect from diseases that are deadly and/or disabling. But they will refuse to believe it because their entire ecosystem depends on the belief that vaccines cause autism. Anything short of that sucks away their life, their reason for living.

One such anti-vaccine zealot is everyone’s favorite “kid.” Even with a master of public health degree in epidemiology, he seems to remain convinced that vaccines cause autism. He’s stated on his blog that evidence he saw in school to the contrary is all a conspiracy from the pharmaceutical industry. It seems that, to him, the lies he has been exposed to over and over from a very young age have made up his mind. To him, Santa Claus (i.e. vaccines cause autism) still exists, and it will continue to exist because anything short of that eliminates his reason for living.

Seriously, he doesn’t seem to live for anything other than that. The primary example is a recent blog post of his where he takes a study that clearly shows that the Tdap (Tetanus, Diphtheria, and acellular Pertussis) vaccine doesn’t cause autism, and then he states that the study confirms that the influenza vaccine does cause autism.

Yeah, I was confused too.

His whole argument hinges on one table in the Prenatal Tetanus, Diphtheria, Acellular Pertussis Vaccination and Autism Spectrum Disorder by Becerra-Culqui et al.

This is table 3:

Screenshot 2018-08-14 10.18.59

Table 3 states that women who were vaccinated with Tdap during pregnancy had a similar incidence rate per 100,000 person-years of having an autistic child. Vaccinated women had an incidence rate of 3.78 autistic children per 100,000 person-years while un-vaccinated women had an incidence rate of 4.05. The ratio between the two was 0.98, meaning that vaccinated women had a lower incidence rate than vaccinated. Anything over 1.0 would indicate that vaccination leads to more autistic children being born.

Because this is one study with a limited number of people, and not a study looking at the entire universe of children born, scientists also report the 95% confidence interval (0.98 – 1.09). The 95% confidence interval is a way of us saying, “We are 95% confident that the true hazard ratio in the entire population (the whole of the population) is between 0.88 and 1.09.” Because it includes 1.0, we cannot say that this observation is not by random chance.

But look at how the kid displays the table on his blog:

Screenshot 2018-08-14 10.18.22

Only point out the things that seem to support your argument.

He points out that the adjusted hazard ratio of 0.85 (with a 95% confidence interval of 0.77 to 0.95) is adjusted for, among other things, influenza vaccination during pregnancy. In epidemiology and biostatistics, “adjusted for” means taking it into consideration. Let me give you an example:

Suppose that there are a group of people from Texas and a group of people from Alabama, and that we look at their test scores in biology. The group from Texas had an average test score of 77% while the people from Alabama had an average test score of 89%. You would conclude that being from Alabama leads you to having a better test score, right?

But what if we told you that they don’t teach biology in all schools in Texas? What if we told you that they only teach it in private schools in Texas, and that only 30% of schools in Texas are private schools? And then we told you that they teach biology in both types of schools in Alabama, and that there is a 50-50 split in the proportion of private to public schools in Alabama? How does this change your conclusion?

To reach the proper conclusion, you have to compare apples to apples, and oranges to oranges. You would compare the private school scores in each state to each other, and likewise with the public school scores. This is an adjustment. This is taking into account the differences in the distributions of a characteristic between the two groups being studied.

As it turns out, in the study in question, women who get their Tdap were much more likely to get their influenza vaccine. It makes sense, right? Women who vaccinate in general are more likely to vaccinate in particular. So, in order to compare apples to apples, the researchers adjusted for influenza vaccination. That is, they compared flu-vaccinated women who got the Tdap and flu-vaccinated women who did not get the Tdap, AND non-flu-vaccinated women who got the Tdap and non-flu-vaccinated women who did not get the Tdap.

Taking flu vaccination into account, and the bias that would creep in because women who vaccinate against influenza seem to be more likely to vaccinated with the Tdap vaccine, vaccinating with Tdap is not associated with having a child diagnosed with autism.

So why does the kid think this proves that influenza vaccine causes autism?

It beats me. All they did was make the adjustment to make things equal between the two groups, something every epidemiologist worth their salt should do… Unless you want to misinform the public?

Hmmmm?

He then takes a table from a different, unrelated study and points out to just one result on it as evidence that influenza vaccine causes autism:

Screenshot 2018-08-14 10.35.03

The red circle seems to be his way of saying, “Only this matters! Pay no attention to the whole of the evidence!”

This is another misrepresentation of the findings, and I kind of blame the authors of the study for making the table so busy. Look at the “Variable” column on the left. All that the data circled in red are saying is this:

“Of the 13,477 children whose mothers were vaccinated in the first trimester, 258 (1.91%) of them were diagnosed with autism. Their hazard was 26% higher for an autism diagnosis when compared to children whose moms were vaccinated in other trimesters. However, when adjusting for maternal allergy, asthma, autoimmune conditions, gestational diabetes, hypertension, age, education, race/ethnicity, child conception year, conception season, sex, and gestational age, the hazard of autism diagnosis went down to 20% over children whose moms were vaccinated in other trimesters.”

The fact that the hazard ratio went down after adjusting tells us that there is something else explaining the elevated hazard (risk). Look at what happened in the adjustment in the other trimester groups… Nothing changed. Look at what happened in the adjustment in the “Anytime During Pregnancy” group… Nothing changed. So what could that “something else” be? I’m not an obstetrician, but it’s reasonable to conclude that outcomes measured in the first trimester are different than outcomes measured in the other trimesters.

Finally, look at the reasoning that the kid used. In the first table, because numbers were adjusted for influenza vaccination, then it must mean that influenza vaccination causes autism. In the second, he doesn’t say that all the factors adjusted for cause autism… Because that would tear down his narrative.

I’m not surprised at all by his misunderstanding of all this. After all, to my knowledge, he doesn’t work as an epidemiologist anywhere. Like any good muscle, lack of practice of your epidemiology skills leads you to lose them. Being unpublished, not working as an epidemiologist, and a staunch defender of the so-called autism-vaccine risk leads the reasoning muscle to atrophy.

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Let’s have a kiki… I mean, a study

They keep asking for it. Antivaccine activists keep asking for a vaccinated vs. unvaccinated study. But they don’t want just any study. They want a study that has as much validity as the most valid epidemiological studies out there: Randomized Clinical Trials (RCTs). RCTs are incredibly difficult to set-up.

To set up a proper RCT you have to do several things. (I know because I had to help set one up for my master’s degree.) You’re looking to compare intervention A (e.g. a drug, a vaccine, or some thing like that) to intervention B. You get a group of people and you randomly assign them to group A or group B. Here’s the thing; you don’t tell them which group they’re in. This is called “blinding.” Otherwise, the people who are getting A and believe that it works might feel better or do things to make it work. It’s happened in real life. A group of people who had diabetes knew that the drug they were being given was not the best drug. So they started watching their carb intake, or continued to use their other medication, or exercised. Needless to say, that kind of skewed things a little. That is called “bias.”

But it’s not just the participants that you keep in the dark. You also have to keep the researchers conducting the study in the dark about which group is which. Say, for example, that you have been paid mad money to conduct the study for drug B. If it fails, you’re out of a job. You’re human, have a family to feed, and really don’t want to go back to waiting tables for a living. If you see that the people on B are not doing too well, you might be inclined to either fudge the results a little bit or put them on an additional drug to make them feel better.

Randomization and “blinding” keeps bias at bay.

The rest of the study is pretty standard. You check for predetermined outcomes like a change in blood pressure values, fasting blood glucose, days of school or worked missed… Things like that. Finally, you compare the two groups for outcomes. Some number crunching later, you determine which of group A or group B is more likely to have the outcome you were measuring, and whether this difference in likelihood was statistically significant.

So why can’t we do this with vaccines?

First of all, we’ve done this with vaccines. Here is the data on what was done to get the HPV vaccine approved. It has been done with other vaccines as well, but you know how anti-vaccine activists are. They don’t want facts to get in the way of their ideas.

Second, we can’t keep vaccines known to work away from children. Why? Because we’d be leaving those in the control group (the unvaccinated group), unprotected from diseases… From some very serious diseases.

Third, anti-vaccine parents will never go for this because there will be a 50/50 chance that their children are immunized. Remember, we randomize the groups into the vaccine or no vaccine groups. We have no control over it, and neither do they. Further, should the anti-vaccine parent find out that their child was vaccinated, do you think that they won’t exaggerate any ailment as being caused by the vaccine or minimize any good outcome — like not missing school due to the chickenpox — and not report it? Bias is a hell of a drug.

Of course, anti-vaccine advocates have come back and said that there are thousands of children who are not vaccinated. Why can’t we go back and look at their medical records and compare those records to vaccinated children?

We can, but what we get from it would be hard to interpret. It would be hard to interpret because these children will have gone to different providers in different healthcare systems at different times and in different locations. Lots of bias there. If we look at only one location, the sample size becomes too small to detect any “signals” in all the “noise.” And then there’s the very real possibility that anti-vaccine parents will tend to be anti-medicine and thus not take their children to licensed healthcare providers, opting for “alternative” providers like chiropractors or wizards, or homeopaths (who might as well call themselves wizards).

So how do we know that vaccines are safe, then?

We know because vaccines have to go through a stringent approval process that includes the agreement of continuing surveillance for adverse events even after the vaccine is “released into the wild.” The vaccines go through several phases of evaluation before they’re licensed to be used. And then, once they’re licensed, healthcare providers, epidemiologists, and scientists are all on the lookout for adverse events. And, contrary to what the anti-vaccine forces will tell you, the adverse events are far and few in between, and they are very rarely catastrophic or even deadly.

To quote a friend, “Anti-vaxxers must think that they win the Power Ball lottery every time they play” because of the way they exaggerate the odds of rare events.

Then again, if you still want to do this study, make sure that you are well-funded. (I’d ask the companies selling alternative medicine supplements and products for the cash.) You’re going to need it if any kids in your control group catch a deadly vaccine-preventable disease and you knowingly kept the vaccine away from them.

Connecting the dots between cause and effect

When I was a child, my teachers used to give us connect-the-dot drawings. I used to happily connect the dots and take the resulting drawing home to my parents. My mom or dad would then post the drawing somewhere for everyone in the home to see. I was really proud of my work, even if it wasn’t real work. All I had to do was go from #1 to #2 and so on until the picture revealed itself to me.

It was something like this:

Not hard to do at all

I’ve often wondered how the mind of someone who believes in outlandish conspiracy theories works. Do they just put the dots together but in a different way?

For example, let’s take this post at the notorious anti-vaccine blog of the (non-existent) epidemic of autism. It starts like this:

“My daughter, Megan, regressed in her physical, mental and social health after vaccinations. Her life forever changed, I am committed to finding out both cause then cure to improve her quality of life, along with so many like her. As a result, I spend a good amount of time reading research and scientific papers to help clarify any connections. Those connections would include immune issues, autoimmunity, mercury and vaccines.”

I highlighted in bold the main gist of that opening statement. This mother, looking for someone or something to blame for her daughter’s atypical neurology, has taken it upon herself to do research. Here’s an article blog post about the author of that post. Here is her Facebook profile. I keep looking and looking and looking some more, and I can’t find anything to tell me about her scientific background.

By the way, she proposes that her daughter developed autism after (and thus because of?) the MMR vaccine:

“Her regression into autism at 18 months developed after her MMR (measles-mumps-rubella) vaccine.”

I mean, if she’s going to do scientific research and dive into scientific studies, then she must have a scientific background that allows her to explain what the studies and papers say to a lay audience, right? If anyone finds out what her background is, please feel free to mention it in the comments. But let’s go back to her blog post on that notorious anti-vaccine blog of the (non-existent) epidemic of autism.

In that post, she mentions that her daughter has an auto-immune disease. So, connecting the dots and using a scientific dissertation and subsequent published paper, she concludes that the mercury in the MMR vaccine caused an auto-immune disorder in her daughter, wich may have led to her daughter’s autism. Never mind that the MMR vaccine never had thimerosal to begin with.

Nevertheless, let’s look at the paper titled “Regulatory Roles for NKT Cell Ligands in Environmentally Induced Autoimmunity“. First, some terminology. “NKT” stands for “natural killer T-cell”. A “ligand” is a molecule that sends a signal, traps another molecule or element, or just plain does something. From an immunology point of view, ligands can make immune responses more vigorous, or even less, depending on the ligand.

The long and short of it is that these researchers gave mice an auto-immune condition by exposing them to inorganic mercury. (Mercury in thimerosal is organic, bound to carbon molecules and, thus, behaving differently.) On top of that, the mice were bred in such a way that exposure to inorganic mercury and even some bacteria would cause their immune systems to go haywire.

I’ve told you before that mice are not people.

How did these mice get an induced auto-immunity, exactly? Like so:

“Mercury-induced autoimmunity was induced according to a standard protocol by three s.c. injections of 30 μg of HgCl2 in 100 μl of sterile PBS at days 0, 2, and 4.”

They got 90 micrograms of inorganic mercury over the course of four days. How much organic mercury in an MMR vaccine? None. How much inorganic mercury in a can of tuna? None. How much organic mercury in a can of tuna? About 70 micrograms.

See what I’m getting at? Organic, inorganic? It’s like saying that salt — aka “Sodium Chloride” — is the same as chlorine gas. It’s not. It’s all in the chemistry. And that’s an important thing to note when you’re talking about these papers to a lay audience of anti-vaccinationists.

The paper continues to note that, yes, and as per their protocol, the mice developed an auto-immune disease. The researchers then went on to look at how the ligands behaved under these circumstances. But that’s not what matters to the blog post author. She hangs on the whole “mercury causes auto-immunity” and “my daughter has an auto-immune condition” and “she also has autism” to basically state that “mercury causes autism”. If this trope sounds familiar to you, it should. It should sound familiar because it’s the trope that a certain British doctor tried to use in hid fraudulent study to link the MMR vaccine to autism. Except that he was smart enough not to say that the MMR vaccine had mercury, which it never did.

She goes on to rant about the ligands, stating that they have been added to vaccines in order to increase the potency of vaccines. In short, it’s all evil. The ligands, the mercury, the non-existent mercury in MMR. Everything. It all causes auto-immune diseases, and, in their mind (the author and the people commenting on her blog post), autism is an auto-immune disorder.

To all this, she concludes:

“It appears that mercury, “abundance as a pollutant, and presence in dental amalgams, cosmetics, preservatives, fumigants, and vaccine preparations ” can cause immune and autoimmune disease via Toll Like Receptors (TLR) activation and then additionally, Man-made, Toll Like Receptors could also have their own influence on immune issues, and very possibly autoimmunity.”

It appears to me that this person, if presented with the brontosaurus connect-the-dot picture above, would come up with this:

If you see a dinosaur, you’re being fooled by the Man

I’m not surprised that this person displays little knowledge of understanding the paper she herself used as evidence. It happens a lot with anti-vaccine and anti-science people. They say that there is a conspiracy, that researchers are being paid by “Big Pharma”, and then they use that same research to try to prop-up their theories.

Someone in the comments section of that blog quoted this paper as clearly showing that vaccines caused all sorts of horrors. Here’s the “Results” section:

“Only in 1 analysis for tics was there some evidence of a higher risk with increasing doses (Cox’s HR: 1.50 per dose at 4 months; 95% confidence interval [CI]: 1.02-2.20). Statistically significant negative associations with increasing doses at 4 months were found for general developmental disorders (HR: 0.87; 95% CI: 0.81-0.93), unspecified developmental delay (HR: 0.80; 95% CI: 0.69-0.92), and attention-deficit disorder (HR: 0.79; 95% CI: 0.64-0.98). For the other disorders, there was no evidence of an association with thimerosal exposure.”

The commenter in question did not understand what “statistically significant negative associations” meant. It means that higher doses showed reduced risk. He or she thought that it meant “negative”outcomes, as in “bad”.

That’s the problem. You have non-scientists trying to make heads or tails out of scientific papers and studies, and they’re misinforming the public in the process.

Merry Christmas, by the way.