the plural of anecdote is not data

When I visited Ben Goldacre’s site the other day, it was apparently down. Then I read at Orac’s place that Ben was in trouble with a radio station in the UK, for posting much of a program that made some rather startling comments & claims about the MMR vaccine. I did a spot of net-surfing & found the program; I listened – & then I had to go & rinse my brains out…

The MMR vaccine is intended to confer protection against measles, mumps & rubella (‘German measles’) – three childhood diseases that used to be fairly common, and which can have fairly high levels of illness associated with them.

Take measles, for example: as many as 1 in 5 people infected by the measles virus can develop complications: ear infections (almost 10% of measles cases), pneumonia (1 in 20), and encephalitis (about 1 in 1,000); 1-2 in 1,000 may die. (According to the Centres for Disease Control website, that death rate can be as high as 1 in 4 in developing countries.) Yes, there can be ill-effects associated with vaccination: as many as 15% of those receiving the measles vaccine may experience some fever &/or swelling at the injection site. But the risk of major adverse reactions – things like encephalitis – affect less than 1 per 1,000,000. In other words, you are several orders of magnitude more likely to become seriously ill from measles than from the vaccination itself.

So I was gobsmacked to hear the radio show’s host comment that "measles & mumps are not that bad really" (particularly when she then went on to say that 1 in 15 used to die of it…). I didn’t listen to all of it; I was starting to say bad words at my computer. But the 15 or so minutes that I heard were a compilation of non-science – personal anecdote (hence my title for this blog), lack of understanding of how the immune system functions – & conspiracy theory ("Hold on a minute – there’s a drug company that’s making lots of money from it [vaccines]." Or "The figures [on vaccine-related incidents] are withheld. I don’t know what they are, because they’ve been withheld." Er, no – anyone with net access can search the VAERS database. Which has issues, because it’s based on self-reporting, but if anything this would lead to over-reporting.)

On anecdote: one caller had 4 unvaccinated children who hadn’t experienced any of the childhood diseases we commonly vaccinate against. Therefore vaccinations aren’t necessary; all that we need (caller & host seemed to agree) was fresh air & exercise. But this is personal anecdote. And the caller was relying on something called herd immunity – in a population where most susceptible individuals are vaccinated, it’s hard for the disease to get a foothold. We rely on herd immunity to protect babies too young to be immunised & those who have compromised immune systems due to illness or chemotherapy. Unfortunately, in both the UK & US, levels of herd immunity have dropped to the point where measles (& other diseases such as whooping cough) are making a comeback.

On the seriousness of those diseases: the host asked, "What is wrong with childhood illnesses… Is there something wrong with having mumps?". For answer, see the data & links above.

On the lack of understanding of immune function: the first caller "knew inherently that is was bad to put ‘toxins’ and ‘poisonous materials’ into a young baby’s body", listing mercury, formaldehyde, and monkey’s kidneys (!) as three of these. There was also a feeling that babies’ immune systems are not able to cope with multiple vaccines like MMR or DPT at one time.

O-kay. Mercury – hasn’t been in childhood vaccines since 2001, nor is there any evidence of harm due to its presence. Formaldehyde – present in tiny concentrations as a result of the manufacturing process (0.1mg in a single dose – compared to about 1.1mg in the average baby’s circulation as a result of normal metabolic processes). And as I’ve said previously, you’re likely to encounter far higher levels in your everyday environment. The host also claimed evidence that children with ‘weak’ immune systems – including, she said, asthmatics – are at risk from vaccination, & said that her daughter, who has asthma, wasn’t vaccinated as a result. But alas – asthma seems to be due to a heightened immune response to some allergens, not a ‘weak’ immune system… And a recent large study found an apparent decrease in asthma symptoms in children who’d received the MMR vaccinations, compared with those who hadn’t. (Children with compromised immune systems – some form of immune deficiency disease, for example – are at risk from vaccination, & it would be contraindicated for them. They are reliant on herd immunity to keep them from harm.)

As for those little immune systems: babies are exposed, from the instant of birth, to an enormous range of potential antigens on a daily basis. Everything they ingest and inhale comes under that category. Certainly our ongoing obsession with hygiene (I mean, do we really need to use antiseptic cleaning sprays & soaps in the home?) may have contributed to an apparent increase in allergies in the ‘developed’ world – but that’s distinct from vaccination & another, very interesting, story.


PS – courtesy of one of Orac’s posters:

A 12 year old French girl died in Geneva recently (January 29th) of measles encephalitis. She was not vaccinated. She had previously been in good health.

Tell me again how this disease is a "mild childhood illness".


Une jeune fille de 12 ans, jusqu’alors en bonne santé, est décédée le 29 janvier dernier aux Hôpitaux Universitaires de Genève d’une encéphalite due à la rougeole. La jeune fille habitait en France, à proximité de la frontière Suisse. Elle n’était pas vaccinée. Ce cas tragique confirme que la rougeole est une maladie dangereuse, souligne l’OFSP.

6 thoughts on “the plural of anecdote is not data”

  • A long post! Maybe a long reply in return… 🙂 I’ve included a coupe of bits for teachers, so I’m not just sounding off. It’s late at night and I’m waiting for Seinfeld to start… sophisticated excuses 🙂 I’m sure there is a Seinfeld episode about that, come to think of it.
    Hey! You’ve duplicated the first two paragraphs, which does make it look longer…! 🙂 Fixed that 🙂 Thank you!
    The VAERS database does suffer horribly from over-reporting and, in case, outright abuse apparently. (Apparently they’ve even had lawyers and anti-vaccine groups feed claims to the database to serve their own ends.)
    I can’t stand those adverts on TV for antiseptic this and that. Crazy. It’s like they want to turn everyone into obsessive compulsives!
    Just over the last couple of days I have run into several articles about vaccines in various places. Reading and trying to correct the anti-vaccine posts is madding. You get all these people saying things they have obviously read somewhere as if their “facts” were “the story”, yet they so obviously lack the skills to judge. And often enough if you try correct them, some loud mouth anti-vaccine person swings in and tries to “win” through bullying.
    A key point that people need, and should be taught at schools, is to recognise that when they don’t know enough to judge for themselves, and to know how to locate genuinely qualified people who can.
    I’d also love to see teachers take a few articles from the media, and show how to critique them. Show the students with a little skill they can do better at fact-checking that, say, TV One or CBS! I’d have to say, that’s not hard to do, unfortunately.
    This one isn’t “media”, but it has a string of simple obvious errors, so it might be useful as a first attempt: Then you could move onto the CBS story that stupid ol’ TV One blithely repeated on the national news without critical analysis:
    (I’d comment on the first one, but they ask for “real” names, and I’ve had it with the bullying approach of some of the anti-vaccine people, for now, anyway. Another is at And the TradeMe “community forum” is so beyond the pale, try not to even remind me about it!)

  • Alison Campbell says:

    Mmmm, Orac has this to say about VAERS: As I pointed out before time and time again, VAERS is very, very sensitive to publicity, which can cause spikes in reports due to the advocacy of well-meaning (or not-so-well-meaning) groups or by lawyers trying to game the database in their favor. Remember, VAERS is an entirely self-reported database. Minimal effort is made to verify reported adverse events, and anything can be reported, whether it can reasonably inferred to have been from vaccines or not. Indeed, two most unusual reports of vaccine “reactions” have been submitted to the database, including a report of a vaccine turning a man into The Incredible Hulk. Indeed, people entering reports don’t even have to originate from the U.S. A couple of years ago, a British father of an autistic girl entered a VAERS report in which he claimed that vaccines turned his daughter into Wonder Woman. VAERS, as I said, is useless for longitudinal studies or determining causality. That’s not its purpose; its purpose is to serve as a “canary in the coalmine,” an early warning system.

  • Alison, thanks for posting this.
    I listened to that recording of that absurd woman’s show.
    How scary to think that people will listen to her and go along with what she says.
    As for that caller who was a trainee homeopath…(Urggg)…

  • Alison Campbell says:

    Yes, I listened (for as long as I could; after that I read the transcripts as they didn’t push my blood pressure up so much!) & thought I really had to post & try to rebut some of the nonsense that was being pushed. (Also showing solidarity with Ben!)

  • Alison Campbell says:

    Yes – I jumped around various blogs to read it, as they’d hosted the transcript piecemeal to get around copyright, I think.
    I think one giveaway phrase to look for is “I’m not an expert, but…” – a phrase that talkshow host used at least twice 🙂

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