Monday, October 13, 2014

The Bleedin' Obvious, Again, From Greg Cochran

A commenter somewhere, my aged memory can't quite remember, recently pointed out that nothing is obvious any more, or can be assumed to be. You have to walk everybody through everything, because the MAG has taught people that facts and logic are optional, if not downright obstacles. So allow me to explicate what should be obvious just a little bit here:

1. Communicable diseases are called that because people who have them can infect other people with them in various ways.

2. The closer such sick people get to other people, the more likely they are to infect them. It's called "proximity."

3. To minimize the chances of such infecting people in country A, where the disease doesn't exit, you should not fly sick people in from country B, where it does exist. And you shouldn't fly anybody from there in, really, unless you can be sure they're not carrying the disease.

4. People from country A should be discouraged from flying to country B, catching the disease, and then flying back. Same logic as in the first three points.

Now, if you're a regular reader of this blog, I'm sure you followed that logic. But it appears to be beyond the capacity of the Obama Administration and all its sycophants to comprehend. If you can think of other ways to explain it that they might find clearer, please send them to me and I'll print them here as a public service.  Meanwhile, here's such an attempt from Greg Cochran, who is one of those scientists who are good at explaining things to laymen. From his blog here:

The Coming Plague
Laurie Garret has an article out in the Washington Post.  She say that there’s no point in trying to block the spread of Ebola by travel bans.
The problem is, she’s full of crap.  Look, there are two possible scenarios.  In both of them, r, the number of new cases generated by each case, is greater than 1 in parts of West Africa – which is why you get exponential growth, why you have an epidemic.  If r < 1.0, the series converges – a case generates a few extra cases before dying out.
Everything we know so far suggests that even though it is greater than 1.0,  r in West Africa is not all that big (maybe around 2), mostly because of unfortunate local burial customs and incompetent medical personnel.
It seems highly likely that r in US conditions is well under 1.0 which means you can’t get an epidemic. However,  r is probably not zero.  It doesn’t mean that you can’t get a few cases per imported case, from immediate contact and hospital mistakes.  As an example, suppose that on average each case imported to the US generated a total of two other cases before dying out (counting secondary, tertiary, etc infections).  Then, on average, the number of US citizens infected would be twice the number of infected visitors.
Now suppose that a travel ban blocked 80% of sick people trying to fly here from Liberia.  We’d have 80% fewer cases in US citizens: and that would be a good thing. Really it would.  Does Laurie Garret understand this?  Obviously not. She is a senior fellow for global health at the Council on Foreign Relations, but she is incompetent.  Totally useless, like virtually everyone else in public life.
We hear people from the CDC saying that any travel restrictions would backfire, but that’s nonsense too.  One might wonder why they say such goofy things: I would guess that a major reason is that they were taught in school that quarantines are useless (and worse yet, old-fashioned), just as many biologists were taught that parasites are really harmless – have to be, because evolution!
In the other scenario, r > 1.0 in US conditions as well, or at least is greater than 1.0 in some subsets of the US population.  This is very unlikely- even more unlikely considering we can adjust our behavior to make transmission less likely.  But suppose it so, for the sake of argument.  Then you would want – need – to stop all travelers from the risky regions, because even one infected guy would pose a huge risk.  Some say that blocking that spread would be impossible. They’re wrong: it is possible*, although it wouldn’t happen, because we’re too crazy.  In fact, in that scenario, we’d be justified in shooting down every plane that _might_ carry an infected passenger.  This scenario is the one that fits Garrett’s remarks, but if she really believed it, she would be frantically buying canned goods and finding a cave in the Rockies to hide her family in.
*the Atlantic is pretty wide.
Quibcag: Again, not really a quibcag. This issue has gone beyond cute.

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