This post is loosely inspired by the fact that some of the US sceptical bloggers, led by surgeon/blogger Orac and the good folks at Science-Based Medicine, have declared this week “Vaccine Awareness Week” (in a good way). They were galvanised into doing this by some of the usual anti-vaccine suspects who had also declared Nov 1-6… “Vaccine Awareness Week” (not in a good way). Anyway, I had hoped to post something more substantive on vaccines and vaccine reactions to join the crowd, but time has run out, and the internet connection is a bit hinky, so I’m afraid this rather navel-gazing piece will have to do.
One of the puzzles of debating people with weird ideas about health, and in particular the anti-vaccine lot, is their attitude to anecdotes.
Most of what one is told by Team Anti-vax “shows” that vaccines have caused harm to children / seizures / autism comes down to anecdotes.
Stories, if you prefer. Or “individual accounts”, if you find “stories” a bit loaded.
Now, there are many problems with stories as a form of evidence.
One is the accuracy with which things have been remembered.
Another is the veracity of the person relating the story.
(This latter can be true even if the person relating the story, or stories, is someone whose relating of them you would expect, for professional reasons, to be as reliable – or as accurate – as possible. Let us mention no Andrew Wakefields in particular.)
But, before I get distracted into a rant about “Saint Andy”, lets just say that stories – or single reports, or anecdotes – have quite a few problems as a form of medical or scientific evidence.
That does not, I should stress, invalidate them.
It just means “handle with care”.
One essential quality of the stories that come from the anti-vaccine people, and those that read, consume, repeat and promulgate them, is that any story that recounts something framed as “child damaged by vaccine” is automatically regarded as believable and accurate. The person recounting them could not possibly have misremembered, conflated, exaggerated, or downright made it up. Even inadvertently.
Indeed, the stories are regarded as so true, and so convincing, that the science that fails to find evidence for the stories’ contention must (in Anti-Vax world) be wrong. Or wrong and evil.This is actually a stock line of the anti-vaccine movement. A particularly florid recent version is here (Warning: contains nuts). A sample quote:
“With voluminous accounts of parents detailing how the problems of their children began after a vaccination it’s nothing less than a crime that the medical authorities stop the science by claiming that the question has been “asked and answered.”
My anecdote = true. Your anecdote = lies.
In marked contrast, however, stories that do NOT back up the Anti-Vaxxers world-view are treated rather differently.
They are regarded, instead, as invented.
I have been having an interesting recent experience of this.
The background: US sceptical Major League doctor-bloggers Orac and Steve Novella have recently been having a public blog argument with Marya Zilberberg, another American doctor and lecturer who runs a blog called Healthcare etc. Zilberberg had posted an article on “The Paternalism of Science based Medicine”, which the other two had called out for committing (as they saw it) a number of errors.
Among the things Dr Zilberberg said was the following:
“The vaccine debate is yet another completely different issue altogether. In our privileged society the specter of infectious epidemics is for the most part but a distant memory, yet our concerns for the safety of our children combined with a rampant, albeit not altogether unjustified, distrust of the pharmaceutical industry and the government, have colluded to promote a biased yet durable suite of misinformation about the risk-benefit profile of vaccinations. Some of this prevailing sentiment may be because, in my opinion, we have focused on the wrong outcomes (e.g., the economics rather than morbidity associated with chicken pox), or that we have overstated what we really know and understand, at the risk of sounding too confident and therefore not trustworthy partners in this important area of public health. But these are just my own speculations. What is more important is what we do know about “science-based” medicine.”
Subsequently, a family physician (GP) in Ohio who blogs as “Dr Synonymous” commented:
“The chicken pox comment alone is worth a lot. I’ve seen many parents who were bullied about the importance of the [chicken pox] immunization by a school nurse or pediatrician. It’s the law in Ohio that you can’t start kindergarten without the cp shot. A sad misuse of our power generates a misuse of legislative power and people feel betrayed, leading to loss of trust in physicians.”
Which prompted Dr Zilberberg to respond:
“Thanks for your comment! Many if not most states require varicella [chicken pox immunisation] for school — agree that it is misuse of power breeding mistrust.”
Now, this annoyed me. Not because I believe in compulsory vaccinations – I don’t, and people should not be bullied to have vaccinations by healthcare workers – but rather because the way it was stated tended to suggest this was an open and shut case, and there was no possible sensible reason for people to have a varicella [chicken pox] vaccination. This struck me as a bit glib. Of course, in the UK we do not vaccinate against chicken pox – we leave children to acquire natural immunity. You can read about the reasons for this policy here. But this is a “judgement call”, and other countries may well make different judgements. I don’t really buy Marya Silberberg’s argument that the US schools ask for vaccination simply because kids with chicken pox otherwise cause parents to have to take two weeks off work. I wonder myself whether it is more a worry of getting sued by the parents of a kid that catches chicken pox at the school. But anyway, I can certainly see reasons why a US school might want to require children to get immunized.
In fact, One of these reasons had been brought home to Mrs Dr Aust and I just the previous week, in a way that will become clear from the following comment I left on Dr Zilberberg’s blog:
“I find the comments here about vaccination from Drs Zilberberg and “Synonymous” quite alarming.
My daughter just brought home a letter from school which asks parents to be “vigilant” about not sending their kids to school with spots. The reason is that there is a little boy in the school who is having treatment for leukaemia and is consequently immunosuppressed.
Unfortunately, non-vaccination is pretty common among the middle class parents of my middle class enclave. And given that kids with varicella will be infectious days before the spots appear, keeping spotty kids out of school is locking the door after the horse has bolted.
From Marya and Dr Synonymous’ words I assume they think it is perfectly reasonable for this poor kid to be put at risk so that other parents can feel smug about exercising their “choice” about vaccinations. I wonder if I am alone in thinking their words will be music to the ears of anti-vaccine campaigners?
Would either Marya or Dr S like to comment on what is likely to happen to this poor boy if he gets chicken pox?
From where I am standing it seems like the legislators in Ohio have a point.”
I also posted a comment over at Respectful Insolence noting the comment I had made at Dr Zilberberg’s:
“[Dr Zilberberg’s] comments on vaccination, and those of a “Dr Synonymous” on her blog, made me quite angry. We just had a letter from our daughter’s school about “don’t send kids to school with spots”, probably because there is a kid in the school under cancer treatment.
Stuff like that tends to make you see requiring things like varicella vaccination for school/kindergarten in a different light.
I’ve left a comment on her blog (in moderation). Assuming it gets posted, will be interested to see what she says in response.”
Now, the story is quite true. We did get a letter. We don’t know precisely what prompted the school to sent it out, as they didn’t say, possibly for reasons of confidentiality. What we do know is that there is a kid in the school (who we know as he lives near us and uses the same playground), who has leukaemia and has been undergoing chemotherapy. He is almost certain to be immunosuppressed. So it is an obvious inference that that is the reason for the letter.
I should say that I didn’t know then what the preferred “resolution” would be in this particular situation; Dr Synonymous responded some time later with:
“I applaud Ohio for all the legislated vaccine mandates except the chicken pox, about which I agree with Dr Z as she previously posted on chicken pox (a whole blog post). Strategies for immuno-compromised children when exposed to vaccine-preventable diseases are included in the NHS Green Book about vaccines”
– the kind of information he referred to seems to be stuff like (e.g.) this and this; which would tend to indicate the child and his parents being tested for varicella immune status, and the parents then being vaccinated in the (unlikely) event that they were not already immune. Plus, if the child were then later exposed to chicken pox, the documents indicate he would need prophylaxis with antivirals or an immunoglobulin shot. Schools are also asked to be vigilant and report cases of chicken pox to parents, presumably partly so that in cases like this “contacts” with the disease can be identified (you can see a typical school policy here – NB PDF).
Now, all that is one approach, and the one the NHS seemingly takes. But you can easily understand why some other jurisdictions might prefer to simply ask for children to be vaccinated before they start school.
[Edit: more about this in the Addendum below]
Anyway, this is by the by. It was the reaction to my remarks from the more anti-vaccine commenters on Dr Zilberberg’s blog that surprised me a little. Here is the first comment after mine
Maybe you have let your emotions get the best of you before you had evidence in your hand.
You post here that a little boy is being treated for cancer AND he is immunosuppressed.
Later on Respectful Insolence you posted that you received a letter from your daughter’s school “probably because there is a kid in the school under cancer treatment.”
It’s seems that you conjured up a scenario that angered you and filled in the conclusions yourself.
This is not what EBM is about.”
And it got worse: here is one of the inevitable Anonymous-es:
“Yes Dr. Aust, it seems you just made up a story about the kid with leukemia.”
And yet another Anonymous, in response to a different commenter who pointed out that what I had said was perfectly internally consistent:
“NO, [Dr Aust] went from a child has cancer to ‘probably’ has cancer. It’s as if he bluffed to one crowd and then went and bragged about it to another. It shows that he never was sure. He assumed it must be. But he felt the need to be more ‘honest’ to his friendly crowd. It shows the intention of deceit.”
As my mate James “jdc325″ commented on Twitter:
“I like that, once it’s been explained, Anon carries on arguing. Of course *they* know what you meant – it’s *you* that doesn’t.
I think the point where you begin reiterating explanations to people who think they know better than you what you meant… …is the point where the head meets the keyboard and you should step away from the computer. Never gonna get through to them.”
But what sticks out for me in all this is the double standard.
Anecdotes from people claiming some form of vaccine damage are always believed. Indeed, as I said earlier, when you express skepticism you are typically told “how can – how dare – you dismiss all this testimony?”
Meanwhile, anecdotes that in any way disagree with the anti-vax worldview are dismissed as deliberate falsifications.
As I put it, somewhat un-diplomatically, on Marya Zilberberg’s blog:
“Trying to discredit the messenger because you don’t want to tackle the substantive point is a wearyingly familiar tactic of anti-vaccine and other “Alternative Reality” folk.
In case anyone cares, I added a clarifying comment above. Sadly, the kid in question definitely has leukaemia. The “probably” was actually referring to the inference about why the school sent out the letter…
However, the Alt.Reality gang routinely accuse opponents and critics of deceit, or of being “Pharma Shills”, or of being part of some sinister organised group – you get this again and again if you puncture their bubble. I suspect they also default to such jibes so readily because it chimes with their own conspiracy fantasies and paranoia. For a look at this kind of tendency in its florid state one only has to take a quick look at a site like Age of Autism.”
Unfortunately, I suspect none of this sort of debating, and no amount of debunking, will influence the significant number of vaccine-averse “Mummy Warrior” types in our primary school here in Middle-Class-shire. The amount of ill-informed sh*t you hear in the playground about “the dangers of too many vaccinations” has to be heard to be believed.
And, though you may find it hard to believe, out of me and Mrs Dr Aust it is actually not me that gets the maddest at hearing this stuff. Though I do usually say something, I am not surprised by what I hear. I have, sadly, become rather inured to the idea that some of our neighbours believe all kinds of daft nonsense about things scientific and medical, usually unencumbered by actually knowing anything.
Mrs Dr Aust, in contrast, despite all her years of dealing with the public, finds it harder just to let this stuff wash over her.
Perhaps, as I have mentioned before, it was things like treating seriously sick adult measles cases on the medical wards. Or seeing kids with Rubella syndrome as a medical student doing an elective in paediatrics.
Anyway, somehow she finds it hard to forget that stuff and “let it all wash over her” when people talk about homeopathy, or fish oils, or blackberry juice being a “natural antiviral” for little Johnny.
Or when they talk nonsense about vaccinations.
Addendum: More on Chicken Pox
After I wrote the bulk of this post on Wednesday night, I was rummaging around on the Internet and found my way, via Respectful Insolence, to an article by the excellent American scientist-blogger Prometheus of A Photon in the Darkness, one of my favourite “mixed” science/pseudoscience blogs.
Prometheus’ excellent post is called “Three Popular Anti-vaccine Myths Deconstructed”. The third of Prometheus’ myths is “The chickenpox vaccine causes shingles!”
The particular reason why I found this interesting is that the NHS Choices page on “Why aren’t children in the UK vaccinated against chickenpox?” states:
“The chickenpox vaccine is not part of the UK childhood vaccination programme, because experts think that introducing a chickenpox vaccination for children could increase the risk of shingles in older people.”
Prometheus argues that the evidence from the use of the vaccination in the US shows that the vaccine strain of varicella is almost certainly not transmissible from children who have been vaccinated to healthy adults. So I guess NHS Choices does not mean “experts think adults could get shingles by catching the vaccine-strain virus from kids who have just been vaccinated”. I suspect that the idea is that in the UK adults regularly get a kind of “booster” to their varicella immunity every time they get near a kid with (wild-type) chicken pox. If the kids only get the (non-transmissable) vaccine strain virus, the adults around them will get no “booster exposure” to varicella, and their immunity may wane quicker; then if they later DO get exposed to a case of wild-type chicken pox, they may get a much worse case of shingles as their immunity will be less.
Of course, there are downsides to the UK policy. First, there is the risk of someone immunosuppressed who has not had chicken pox catching it (see my story above about our daughter’s school) And second, there is the risk of someone older whose varicella immunity has run down being exposed to wild-type chicken pox and getting a nasty case of shingles.
In fact, I was interested to see there are currently proposals afoot to give people in Britain over 70 the varicella vaccination, the idea being to “top up” their immunity to the virus and thus prevent them getting shingles, either via viral re-activation (re-activation of varicella lurking in their sensory nerve cells, which is what the stuff does if your immunity gets low enough) or via exposure to an individual with chicken pox.
Now, I should say that the above is my interpretation of what I have read on the websites and on Prometheus’ blog. I am not a virologist of even a medical doctor, so there may be some inaccuracies in what O have written. Perhaps if DeeTee still reads the blog he can advise me whether I got all of this right.
The point, really, is that in mainstream medicine evidence is always developing, and policies based on the evidence are regularly under review. Currently, there is mass child vaccination with the varicella vaccine in many parts of the US, but not the UK. Does that imply disagreement? I don’t think so. They are simply different approaches to the problem of “managing” chicken pox/varicella in the population. And it is always possible that the policy in either country may change in the future. The reasons for the difference seem to hinge on the debate about how quickly the “lifelong immunity” conferred by childhood infection wanes, and the best way to manage the immune status of the community as a whole to make sure people are not exposed to the risk of shingles (or, more dangerously, chicken pox) late on in life. Which sounds like an interesting public health question, of the kind that public health doctors and epidemiology people would be found debating with their computer models.
In the meantime, though, one is still left with – mass varicella vaccination? Or not?
To which the answer is – I don’t know, but it’s an interesting question.
Which is fine. Scientists, and doctors too, are generally comfortable with a bit of “don’t know” – with uncertainty. It is part of the business of science and medicine, because, as just mentioned, scientific and medical evidence is not a constant, but a changing body of information. Contrast Alt Med people – who, regardless of their mantra of “Let’s keep an open mind” usually aren’t happy with uncertainty and changes to what is known. After all, they already know they are right. They are just waiting for the evidence to catch up with them.
Note: I’m not sure if those final two sentences were ironic or depressed.