Only after you hit the HIT (Herd Immunity Threshold); below that, pretty much everyone who can get the disease, will, if it has a long contagious period prior to onset of symptoms, is contagious after symptoms remit and the person is not educated that they need to stay home longer, even if they "feel better", or the disease has asymptomatic carriers. Or some jerk decides to "work through it", and exposes their coworkers.

And as the math proves, measles and pertussis have an HIT too high to be able to pop over the top of the HIT to get to that saddle point. Their only saving grace is that people isolate themselves when they feel ill.

NB: measles is infectious 4 days before onset of symptoms, and up to 4 days after symptoms remit; pertussis, at least, is only infectious after onset of symptoms, and remains infectious for only 3 weeks (but symptoms last longer, if untreated with antibiotics); if treated with antibiotics, pertussis is no longer infectious after about a week. Measles is pretty insidious.

It's called a crock pot.

This slows the burn rate.

Read Richard Preston's "The Hot Zone". The reason Ebola is such a non-problem is that it has a very high burn rate: from acquisition of the disease to death is a short path, and therefore, without outside help, it has a hard time traveling very far before all the carriers are either immune (small percentage) or dead (most of them).

Counterintuitively, a slow burn rate is actually a *bad* thing, for an infectious disease, and the more infectious the disease, the *worse* things are, if the disease has a slow burn rate.

As an historical example: Typhoid Mary's burn rate was 0.

That was primarily due to defacto quarantine, not immunization. When someone is home sick, or in the hospital in isolation sick, they are not in contact with people who are susceptible, but have not yet contracted the disease.

This is an incredibly important effect for hyper-virulent diseases like measles.

Actually, that's not precisely what it means. What it means is that the herd has an immunity above the HIT, and therefore an infectious disease will burn itself out before it becomes endemic (*en*demic, NOT *epi*demic).

You are aware of what "herd immunity threshold" and "R(0) value" for a disease, mean, right? If not, let me refresh your memory:

http://en.wikipedia.org/wiki/H...

As you can see from the chart, the R(0) of measles is sufficient for some strains to require a 94% immunity in the population before the disease will burn itself out, rather than transmitting to a susceptible individual.

Since 6% of people can't be immunized (too young, Hep C, bad histamine complex on chromosome 6, immunocompromised by HIV or other infection, organ transplant, and so on), that requires *everyone else* be immunized.

In addition, if you read the text to the left of the R(0) chart, you'll see that the population has to be homogeneous for this to be meaningful. So what this means is that unimmunized people have to be uniformly distributed throughout the population. Which they are not.

Feel free to then drop down to the equations in the next section, and do the math for measles and pertussis.

Then come back, and we can talk more.

Ask me again after you've opened the box and agreed to the shrink wrap license on the D-Wave you just bought...

Of course, you are aware that due to medical inability for 6% of people to be vaccinated, and a non-zero vaccine failure rate, and the fact that we do not perform post-vaccination immunoassay to verify that the vaccination has been effective (and then revaccinate the shit out of the person until an immunoassay shows it to be effective), therefore herd immunity for measles and pertussis is mathematically impossible.

Right?

You *should* get vaccinated for these diseases, and you *should* get your kids vaccinated for these diseases. If the vaccine is effective, which for measles, it is 61% of the time according to a recent WHO study in Buenos Ares, Argentina, then you've saved your ass, or you've saved your kids ass.

But you are totally a moron if you believe that you are doing this out of altruism, rather than out of a selfish desire to save your own ass, because you will not, in fact, prevent either outbreaks or spread of these two diseases.

Particularly if we let people from hot zones with known active outbreaks fly into the U.S. with no border procedures to prove they don't have the diseases, and then let them go to Disneyland and infect the 39% of the 94% who are vaccinated (but for which the vaccine was ineffective), or the additional 6% who are immunocompromised to the point they can't tolerate being vaccinated.

P.S.: Now if you want to pick a different example, like Polio, chickenpox, or smallpox: yes, it's possible to achieve herd immunity. But most idiots who are bad at math tend to use measles or pertussis as their examples, because the outbreaks are always in the news (hint: because they are impossible to prevent via any method other than quarantine, and that's politically correct, even if we are talking about Ebola, for which there is no vaccine).

I thought that was Greenpeace.

And isn't their thing these days defacing world heritage sites in more or less irreversible and environmentally damaging ways?

Ironically?

Given the way things are going, probably the Opportunity Mars Rover...

Totally historically inaccurate, but let's address whether it's a bad example; it's not.

Actually, it's a great example.

The current article was written just before the collapse of the American empire.

This is basically an air show, with aircraft from two fields merging into a single stream of 15 formations. Formations 1, 4, 7, 11, and 15 will each contain a heterogeneous set of aircraft, in some cases mixing planes from different eras. Many of the aircraft are flying on "experimental" certifications.

This is not the same thing as flying a long distance from point A to point B and being able to follow a filed flight plan.

VIDEO: https://www.youtube.com/watch?...

https://www.youtube.com/watch?...

Would have gotten away with it too, if it weren't for those meddling kids and their mangy mutt...

Makes me want to buy someone a ton of bricks. Then the drone can drop it on them, no matter where they are.

Too bad the protesting postman didn't just wait for the event, and fly a vintage autogyro.

Just sayin'...

Lack of modern istrumentation, radar transponders, and other equipment which is normally used by modern air traffic control systems. You will recall that the newly overhauled system went online 7 days ago (30 Apr 2015):

http://www.usatoday.com/story/...

The primary issue won't be in the corridor itself, it'll be getting into and out of it from shared public airspace, and avoiding collisions between the aircraft themselves, many of which do not have anti-collision systems or even radars.