What does an anti-vaccine activist want?

With the swelling of interest in the anti-vaccine movement, inspired by the recent California measles outbreak, I’ve seen a number of opinions published similar to this one from Ian Steadman in the New Statesman

Then there’s also this to think about: if somebody’s distrust of scientific and/or political authority is so great, for whatever reason – maybe they’ve been scared by sensationalist stories in the media, or maybe they sincerely believe the government has no moral right to dictate health choices to citizens – that they’re willing to significantly increase their child’s risk of catching a (possibly fatal) illness, then calling them names and telling them scientists and politicians disagree with them is probably futile. Arguing that “the science is settled” with someone whose stance is predicated on the belief that the standards of proof used by scientists are flawed is definitely futile.

The article is excellent, but I don’t entirely agree with this sentiment. Living in Berkeley and Oxford, I have encountered some vaccine refuseniks, and it’s not clear to me that they have anything as definable as a belief about “the standards of proof used by scientists”. Rather, I think that they have a desperate need to feel special, protected not by mass vaccination — and definitely not by anything as infra dig as “herd immunity” — but by their special virtue, which may be Christian purity or organic health-food purity. Continue reading “What does an anti-vaccine activist want?”

The CDC misunderstand screening too

Last week I mocked the Spanish health authorities who refused to treat an Ebola-exposed nurse as a probable Ebola case until her fever had crossed the screening threshold of 38 degrees Celsius (or, in the absurdly precise American translation, 100.4 degrees Fahrenheit). Well, apparently the Centers for Disease Control in the US aren’t any better:

Before flying from Cleveland to Dallas on Monday, Vinson called the CDC to report an elevated temperature of 99.5 Fahrenheit. She informed the agency that she was getting on a plane, the official said, and she wasn’t told not to board the aircraft.

The CDC is now considering putting 76 health care workers at Texas Health Presbyterian Dallas hospital on the TSA’s no-fly list, an official familiar with the situation said.

The official also said the CDC is considering lowering the fever threshold that would be considered a possible sign of Ebola. The current threshold is 100.4 degrees Fahrenheit.

Most disturbing is the fact that they don’t seem capable of combining factors. Would it be so hard to have a rule like, For most people, let’s hold off on the hazmat suits until your fever goes above 38. But if you’ve been cleaning up the vomit of an Ebola patient for the past week, and you have any elevated temperature at all — let’s say 37.2 — it would be a good idea to get you under observation.

One-fifth of a teaspoon

I was brought up short by this odd sentence in a NY Times article on attempts to protect health-care workers treating Ebola patients:

At the peak of illness, an Ebola patient can have 10 billion viral particles in one-fifth of a teaspoon of blood. That compares with 50,000 to 100,000 particles in an untreated H.I.V. patient, and five million to 20 million in someone with untreated hepatitis C.

“One-fifth of a teaspoon” is an odd reference unit. I had to think a moment to realise that the reporter had presumably translated into American from Scientific the sentence

At the peak of illness, an Ebola patient can have 10 billion viral particles in one milliliter of blood.

As I discussed before, the partial conversion to the metric system has left fault lines between and within nations. And the attempt to cover over those cracks mechanically creates odd dissonances. Thus, the 19th century estimate of average human body temperature of 37 degrees Celsius (plus or minus about half a degree) gets turned into the incredibly precise sounding 98.6 degrees Fahrenheit. It makes as much sense as saying “28 grams of prevention are worth 454 grams of cure”.

If the reporter had thought about it, she might have translated less mechanically, writing “an Ebola patient can have 50 billion viral particles in a teaspoon of blood”. But that still leaves the weird resonance of “teaspoon of blood”. A millilitre can be water or blood or Martian atmosphere, but when I hear “teaspoon” I subliminally feel like it’s supposed to go in my tea, or cake, or soup. The thing that people like so much about these traditional units is their historical and narrative specificity, their attachment to human-scale measuring activities, but that also makes them awkward for transferring measurements between domains. I could state my height in furlongs, and my weight in grains, but I’ll just confuse people.

Before posting, I just wanted to check that I was right about the size of a teaspoon in milliliters. I asked Google, and received the information “1 Imperial teaspoon =5.91939047 millilitres”. So, first of all, I was surprised to learn — if indeed it is true — that the teaspoon has been standardised to the hundred-billionth of a litre. Second, I found the thought of “the imperial teaspoon” hilarious.

Political talk therapy

Two apparently unrelated items from Nick Clegg’s speech at the Liberal Democrats’ party congress: First the BBC quoted his exhortation to the party soldiers, that they should

go to the next election with their “heads held high”.

Then came his announcement of

the first national waiting time targets for people with mental health problems.

People with depression should begin “talking therapy” treatments within 18 weeks, from April.

Let’s see: If the depressed Liberal Democrats can get their talk therapy started in April, maybe they’ll hold their heads a bit higher by the 7 May election.

False positives, false confidence, and ebola

Designing a screening test is hard. You have a large population, almost all of whom do not have whichever condition you’re searching for. Thus, even with a tiny probability of error, most of the cases you pick up will be incorrect — false positives, in the jargon. So you try to set the bar reasonably high; but set it too high and you’ll miss most of the real cases — false negatives.

On the other hand, if you have a suspicion of the condition in a particular case, it’s much easier. You can set the threshold much lower without being swamped by false positives. What would be really dumb is to use the same threshold from the screening test to judge a case where there are individual grounds for suspicion. But that’s apparently what doctors in Spain did with the nurse who was infected with Ebola. From the Daily Beast:

When Teresa Romero Ramos, the Spanish nurse now afflicted with the deadly Ebola virus first felt feverish on September 30, she reportedly called her family doctor and told him she had been working with Ebola patients just like Thomas Eric Duncan who died today in Dallas. Her fever was low-grade, just 38 degrees Celsius (100 degrees Fahrenheit), far enough below the 38.6-degree Ebola red alert temperature to not cause alarm. Her doctor told her to take two aspirin, keep an eye on her fever and keep in touch.

She was caring for Ebola patients, she developed a fever, but they decided not to treat it like a possible case of Ebola because her fever was 0.6 degrees below the screening threshold for Ebola.

A failure of elementary statistical understanding, and who knows how many lives it will cost.

Blaming the victim: Antibiotic edition

Having failed to hold back the tides, King Camerute is now taking on the worthy task of stemming the flood of antibiotic resistant microbes, according to a report on the front page of today’s Times. On the inside pages we have an opinion piece by one Theodore Dalrymple, under the title

Patients, not GPs, are to blame for the antibiotics crisis

Since GPs are responsible for prescribing most of the antibiotics in this country, I was curious how they were not to blame. I assumed the story would take one of two tacks (or both):

  1. Patients are obtaining prescriptions under false pretences, perhaps by exaggerating or misrepresenting their symptoms.
  2. Patients are somehow acquiring antibiotics without prescriptions.

Neither of these is mentioned. In fact, despite the headline — which Dr Dalrymple is presumably not responsible for — the article states clearly “The real problem we face is the over-prescription of antibiotics in ordinary medical practice.” Patients are never mentioned in the article until the last paragraph, which states, in full

And, hard though it ma be for some to accept, it would help if patients took their GPs’ advice rather than demanding the drugs they want. Doctor really does know best.

Well, that’s it then. The responsibility does not lie with the GP who actively wrote a prescription. It lies with the stupid but strangely powerful patient who “demanded” it. And it gets worse. We live, it seems, in a “litigious age and doctors are afraid”.

There is, after all, more rejoicing by malpractice lawyers over one missed diagnosis than over 99 people treated unnecessarily with antibiotics.

Presumably the author thinks they should rejoice more over all the people treated unnecessarily with antibiotics? I’m confused. In any case, they’re bad people, so anything that makes them happy is bad for the rest of us.

I’m no expert in British law, but why would a treatment with unnecessary antibiotics prevent a lawsuit? How many doctors have actually been sued, under circumstances where a random antibiotic prescription might have forestalled the lawsuit? Dr Dalrymple doesn’t even have a silly anecdote to offer.

Or could it be that overworked GPs find prescribing antibiotics to be a convenient substitute for actually talking to the patients? Dr Dalrymple, we learn at the bottom, is a “retired prison doctor” which, I think, helps to explain where he acquired his exquisite contempt for patients.

Lazy headline clichés: Obesity edition

Am I the only one who is briefly bemused when a Guardian homepage headline refers to obesity “leaping” in the developing world, or when the headline on the article tells us

Obesity soars to ‘alarming’ levels in developing countries

I understand the need for colourful imagery in headlines, but it shouldn’t clash. Thinking about obesity leaping and soaring makes my head hurt. We might imagine a headline about a “Healthy increase in measles cases”, or “New NHS rules allow GPs to make a killing”.

The striving after punchy language sometimes makes for weird effects when combined with the English language’s exceptional parts-of-speech ambiguity, as in this BBC headline from the time of the BP oil leak in the Gulf of Mexico:

BP caps shattered oil leak wellhead

At first I thought BP had put some caps on, which proved counterproductive because they shattered the wellhead. I forgot that headline writers like to put everything in the present tense (sounds more exciting that way, I guess), so what I thought was a noun (caps) was actually the verb, describing a success, and what looked like a past-tense verb describing the failed effort was actually a participle, referring to the state of affairs that started the whole story.

The cost of anti-terror

By way of Brendan James at The Dish comes this report by Ben Richmond on the disruption of vaccination efforts in rural Pakistan caused by the CIA smuggling a spy into Osama bin Laden’s refuge disguised as a health worker distributing hepatitis B vaccines. I won’t question the justice of killing bin Laden, nor will I call it useless because bin Laden may have been, by that point, barely even a figurehead of al Qaeda. I appreciate the value of propaganda by force in the important struggle against violent Islamists.

But when we reckon the costs against the benefits of killing terrorists, let us consider the 22 vaccination workers killed and 14 injured in retaliation attacks, or the many thousands who will be killed or maimed by polio, now that the realistic hope of soon eradicating that horrible disease has been set back, perhaps for a very long time. One wonders iƒ the cost to public health had any place in President Obama’s decision-making in approving this particular CIA operation. Is there anyone who speaks up for non-American interests? Is there any number of  lives of the poor bystanders for whose sake a US president would judge it worth giving up a symbolic victory in the struggle to save American (and wealthy western more generally) lives? Other than because of threats of diplomatic or military retaliation against Americans.

I’d be genuinely interested if any political theorist has thought through how this calculus works.

Total Impact: Wakefield edition

So it seems Andrew Wakefield is back in the news. As Phil Plait has described well, the man who has done more to undermine public health than any physician since Martini and Rodenwaldt has been given space in The Independent to accuse the British government of inadequate measles prevention. Because his rantings scared lots of parents off the MMR vaccine, and the NHS didn’t want to provide separate measles vaccines instead.

The pathological self-promoters you will have with you always, so there’s no real surprise there. But it got me to thinking about his future in British medical research. Because some denizens of less enlightened lands may not know how IMPACTFUL British research has become: The prime directive for state-sponsored research under the current government (though I think it started already under Labour) is “impact”, defined as

an effect on, change or benefit to the economy, society, culture, public policy or services, health, the environment or quality of life, beyond academia

because academia is just a province of Faerie, not an actual part of the society or economy. In addition to impact being a crucial part of every grant proposal, and the postmortem on every grant after it’s completed, this definition will guide 20% of the scoring on the Research Excellence Framework (REF) just now getting underway, replacing the Research Assessment Exercise (RAE) last conducted six years ago, because now instead of research being assessed, we agree that it’s all excellent but needs to be frameworked, or something.

So anyway, it’s noteworthy that BENEFIT is only one acceptable form of impact. Any change or effect gets you points for impact, rather in the way the bibliometric citation counting that prevails in many academic fields doesn’t distinguish between citations for your paper providing key insights that inspired follow-on research, and citations that point out yet another bone-headed mistake in the paper that has been confusing researchers and holding back the progress of the field.

What’s more, it’s not clear how anyone would evaluate whether those who benefit from the research are themselves providing a net benefit or harm to society. (Sorry, I mean, to the taxpayer. There’s no such thing as society.) Presumably no one will provide a support letter from bioterrorists, explaining how their headline-generating work would have been impossible without the groundbreaking research of Professor X, but someone like David Li could show evidence that his work formed the industry-wide basis for the multi-billion pound market in mortgage backed securities which (you may have heard) helped to crash the world economy. The fact that he might himself agree that his formula never should have been applied, that the bankers “misinterpreted and misused it“, and that “Very few people understand the essence of the model“, doesn’t detract from the benefit that derived to some people, at least in the short term, and even the worst recession in 75 years certainly counts as a “change in the economy”, demonstrating the IMPACT of the research.

With that in mind, I reveal the hitherto secret Wakefield Impact Case Study, titled “Royal Free Hospital School of Medicine characterisation of risk factors for Autism and Vaccination Policy”. We are confident that the massively impactful Wakefield will quickly be hired by a major research institution and showered with research grants. Continue reading “Total Impact: Wakefield edition”