Archive for May, 2015

More on Vaccination

Friday, May 15th, 2015


One issue that I am fairly militant about is vaccination. Vaccines are arguably the greatest invention in human history. Vaccines made smallpox, a disease that slaughtered billions, extinct. Polio, which used to maim and kill millions, is on the brink of extinction. A couple of weeks ago, Rubella became extinct in the Americas:

After 15 years of a widespread vaccination campaign with the MMR (measles-mumps-rubella) vaccine, the Pan American Health Organization and the World Health Organization announced yesterday that rubella no longer circulates in the Americas. The only way a person could catch it is if they are visiting another country or if it is imported into a North, Central or South American country.

Rubella, also known as German measles, was previously among a pregnant woman’s greatest fears. Although it’s generally a mild disease in children and young adults, the virus wreaks the most damage when a pregnant woman catches it because the virus can cross the placenta to the fetus, increasing the risk for congenital rubella syndrome.

Congenital rubella syndrome can cause miscarriage or stillbirth, but even the infants who survive are likely to have birth defects, heart problems, blindness, deafness, brain damage, bone and growth problems, intellectual disability or damage to the liver and spleen.

Rubella used to cause tens of thousands of miscarriages and birth defects every year. Now it too could be pushed to extinction.

Of course, many deadly diseases are now coming back thanks to people refusing to vaccinate their kids. There is an effort to blame this on “anti-government” sentiment. But while that plays role, the bigger role is by liberal parents who think vaccines cause autism (you’ll notice we’re getting outbreaks in California, not Alabama). As I’ve noted before, the original research that showed a link between vaccines and autism is now known to have been a fraud. Recently, we got another even more proof:

On the heels of a measles outbreak in California fueled by vaccination fears that scientists call unfounded, another large study has shown no link between the measles-mumps-rubella vaccine and autism.

The study examined insurance claims for 96,000 U.S. children born between 2001 and 2007, and found that those who received MMR vaccine didn’t develop autism at a higher rate than unvaccinated children, according to results published Tuesday by the Journal of the American Medical Association, or JAMA. Even children who had older siblings with autism—a group considered at high risk for the disorder—didn’t have increased odds of developing autism after receiving the vaccine, compared with unvaccinated children with autistic older siblings.

96,000 kids — literally 8000 times the size of the sample Wakefield had. No study has ever reproduced Wakefield’s results. That’s because no study has been a complete fraud.

There’s something else, though. This issue became somewhat personal for me recently. My son Ben came down with a bad cough, a high fever and vomiting. He was eventually admitted to the hospital for a couple of days with pneumonia, mainly to get rehydrated. He’s fine now and playing in the next room as I write this. But it was scary.

I mention this because one of the first questions the nurses and doctors asked us was, “Has he been vaccinated?”

My father, the surgeon, likes to say that medicine is as much art as science. You can know the textbooks by heart. But the early symptoms of serious diseases and not-so-serious one are often similar. An inflamed appendix can look like benign belly pain. Pneumonia can look like a cold. “Flu-like symptoms” can be the early phase of anything from a bad cold to ebola. But they mostly get it right because experience with sick people has honed their instincts. They might not be able to tell you why they know it’s not just a cold, but they can tell you (with Ben, the doctor’s instinct told him it wasn’t croup and he ordered a chest X-ray that spotted the pneumonia).

Most doctors today have never seen measles. Or mumps. Or rubella. Or polio. Or anything else we routinely vaccinate for. Thus, they haven’t built up the experience to recognize these conditions. Orac, the writer of the Respectful Insolence blog, told me of a sick child who had Hib. It was only recognized because an older doctor had seen it before.

When I told the doctors Ben had been vaccinated, their faces filled with relief. Because it meant that they didn’t have to think about a vast and unfamiliar terrain of diseases that are mostly eradicated. It wasn’t impossible that he would have a disease he was vaccinated against — vaccines aren’t 100%. But it was far less likely. They could narrow their focus on a much smaller array of possibilities.

Medicine is difficult. The human body doesn’t work like it does in a textbook. You don’t punch symptoms into a computer and come up with a diagnosis. Doctors and nurses are often struggling to figure out what’s wrong with a patient let alone how to treat it. Don’t cloud the waters even further by making them have to worry about diseases they’ve never seen before.

Vaccinate. Take part in the greatest triumph in human history. Not just to finally rid ourselves of these hideous diseases but to make life much easier when someone does get sick.

Movie Review: Interstellar

Saturday, May 9th, 2015

So far, I have seen five of last year’s Best Picture nominees — Birdman, Boyhood, The Grand Budapest Hotel, The Imitation Game and Whiplash. I’ve also seen a few other 2014 films — Gone Girl, Guardians of the Galaxy and The Edge of Tomorrow — that rank well on IMDB. I’ll have a post at some point about all of them when I look at 2014 in film. But right now, they would all be running behind Interstellar, which I watched last night.

I try very hard to mute my hopes for movies but I was anticipating Interstellar since the first teaser came out. I’m glad to report that it’s yet another triumph for Nolan. The film is simply excellent. The visuals are spectacular and clear, the characters well-developed, the minimalist score is one of Zimmer’s best so far. The ending and the resolution of the plot could be argued with but it’s unusual for me to watch a three-hour movie in one sitting unless it’s Lord of the Rings. I definitely recommend it, especially to those are fans of 2001 or Tree of Life.

That’s not the reason I’m writing about it though.

One of the remarkable things about Interstellar is that it works very hard to get the science right. There are a few missteps, usually for dramatic reasons. For example, the blight affecting Earth works far faster than it would in real life. The spacecraft seem to have enormous amounts of fuel for planetary landings. The astronauts don’t use probes and unmanned landers to investigate planets before landing. And, as I mentioned, the resolution of the plot ventures well into the realm of science fiction and pretty much into fantasy.

But, most of the film is beautifully accurate. The plan to save Earth (and the backup plan) is a realistic approach. Trips through the stellar systems take months or years. Spacecraft have to rotate to create gravity (including a wonderful O’Neill Cylinder). Space is silent — an aesthetic I notice is catching on in sci-fi films as directors figure out how eerie silence is. General and special relativity play huge roles in the plot. Astrophysicist Kip Thorne insisted on being as scientifically accurate as possible and it shows.

And the result is a better film. The emotional thrust of Cooper’s character arc is entirely built on the cruel tricks relativity plays on him. The resolution of Dr. Mann’s arc is built entirely on rock solid physics including the daring stunt Coop uses to save the day. The incredible sequences near the black hole could be taken right of a physics textbook, including a decision that recalls The Cold Equations.

We’re seeing this idea trickle into more and more of science fiction. Battlestar Galactica had muted sounds in space. Moon has reasonably accurate scientific ideas. Her had a sound approach to AI. Serenity has a silent combat scene in space, as did, for a moment, Star Trek. Gravity has some serious issues with orbital dynamics, but much of the rest was rock solid.

I’m hoping this will continue, especially if the rumors of a Forever War movie are true. A science fiction movie doesn’t need accurate science to be good. In fact, it can throw science out the window and be great (e.g., Stars Wars). But I hope that Interstellar blazes a path for more science fiction movies that are grounded, however shakily at times, in real science. This could breath new life into a genre that’s been growing staler with every passing year.

I don’t say this as an astrophysicist (one available for consultation for any aspiring filmmakers). I say this as a movie buff. I say this as someone who loves good movies and think great movies can be made that show science in all its beautiful, glorious and heart-stopping accuracy.

Post Scriptum: Many of my fellow astronomers disagree with me on Interstellar, both on the quality of the film and its scientific accuracy. You can check out fellow UVa alum Phil Plait here, although note that in saying it got the science wrong, he actually got the science wrong. Pro Tip: if you’re going to say Kip Thorne got the science wrong, be sure to do your homework.

Mathematical Malpractice Watch: IUDs and Teens

Thursday, May 7th, 2015

Right now, the liberal blogosphere is erupting over Republican plans to not fund a program to give free IUDs to low income women:

Republican legislators in Colorado will not authorize funding for a program that gives free IUDs to low-income women — an effort that many believe was responsible for hugely driving down teen births.

Colorado has recently experienced a stunning decline in its teen birth rate. Between 2007 and 2012, federal data shows that births declined 40 percent — faster than any other state in the country.

State officials attributed part of this success to the Colorado Family Planning Initiative, which provided free IUDs to low-income women seen at 68 family planning clinics across the state. Last year, state officials estimated that young women served by those family planning clinics accounted for about three-fourths of the overall decline in Colorado’s teen birth rate.

I disagree with the Republicans on this. But the idea that free IUD program cut Colorado’s teen birth rate by 40% or 3/4 of 40% or anywhere close to 40% is high-test nonsense.

Here is the data from the CDC on teen brith rates. From the first graph, you’ll see that teen birth rates have been steadily falling for seventy years. Like most positive social trends, it has many, um, parents, each of which are flogged by whomever supports that particular issue. Availability of contraception has certainly played a role. The legalization of abortion played a role (although abortion rates peaked in the early 80’s). As social and professional barrier have fallen, many more women are delaying pregnancy for college and jobs. And there is some evidence that teenagers are waiting longer to have sex (that would be the dreaded “abstinence”).

Since 2007, however, the teen birth rate has fallen off a cliff. But not just in Colorado. It’s fallen everywhere, by an average of 30%. If anything, it’s fallen faster in red states than in blue ones (see Figure 9 of the CDC’s report). Colorado has seen the steepest decline (39%), but just behind it are the red states of Arizona (37%), Georgia (37%), North Carolina (34%), Utah (34%) and Virginia (33%).

Is Colorado’s IUD program so awesome that it dropped the teen birth rate for the entire country?

Given the extent of the program and Colorado having the largest reduction, it’s very probable that the IUD program did play a role here. But I would ballpark it at maybe 10% at the most.1 That’s not nothing and it’s probably worth continuing the program. But let’s not pretend the reduction is due only to that.

So what is causing the large reduction? Availability of contraception is playing a role, yes, but there’s something else going on. Birth rates have fallen for all women since 2007, not just teenagers. I don’t think it’s coincidence (and neither does the CDC) that the teen birth rate plunged when we hit the worst recession since the Great Depression. If you look at historical birth rates, you’ll see a similar plunge in during the 1930’s. And that was long before almost the entirety of modern birth control, least of all free birth control.

I think that’s the story here. Colorado’s program was fortuitously timed in that regard and there is likely some synergy between the economic downturn and the IUD program (i.e., the program kicked in right when a bunch of women were more eager for birth control).

One of the difficult things about Mathematical Malpractice Watch is that I frequently end up attacking people I fundamentally agree with. I think Colorado should extend their IUD program (although I’m old enough to remember, in the 90’s, when Republican governors offering incentives for low-income women to use Norplant was denounced as eugenics). But the claim that it has produced a “huge” reduction in the teen birth rate is just not true.

Actually, there is a chance that the effect is 0%. Colorado had the sharpest reduction in teen pregnancy rates. It’s easy to go in, post facto, and identify a pet policy to pin it on while ignoring the thousand other factors occurring in fifty states. It’s called the Texas Sharpshooter Fallacy. Colorado might just be a statistical outlier and we’re crediting a policy for that outlierness because we like the policy. Colorado’s barely two standard deviations from the mean. I think it’s likely the IUD fund had an effect, but I’d be pressed to prove it statistically.