Over 150 unvaccinated students in South Carolina quarantining after measles exposure

[progree]

18. I'm just curious about the percentage anyway

Last edited Mon Oct 13, 2025, 01:22 PM - Edit history (6)

From the article:

"It is an extremely effective vaccine, so about 93% on the first dose and 97% effective on the second dose," she said.

So, if, for example, 40% of the Minnesota cases were vaccinated and 60% were not, that would still be 'most were unvaccinated', but it would be way outside the expected probability.

The Wisconsin statistic that all 36 cases were unvaccinated actually is a bit of an outlier in the other direction -- even with a 97% effectiveness rate. The chance of that statistically is 33%, with a 67% chance of 1 or more of the cases having been vaccinated.

Nobody here is arguing that MMR vaccinations are not very very effective. Some people are just interested in the numbers and egghead stuff like probablility and statistics, and some are not, and that's OK, DU is a diverse community. and we're a big tent. It happens.

Edited to add Actually, it's more than just an egghead exercise. If, for example, 40% of the 20 cases were vaccinated, it would be so far outside the expected probability that an investigation would probably be undertaken as to why. Bad batches? A mutation? Statistical analysis is used to find potential problems.

Edited to add after a couple of comments:

I have doubts about my statistical look at the Wisconsin cases. Although I've had about 4 university level statistical courses, and hundreds of hours of self-study, those were decades and decades ago. I'm also impressed by books like "Innumeracy" by John Allen Paulos, and by other counter-intuitive examples, where people can go astray.

In the Wisconsin cases, I'd add that even calling it "a bit of an outlier" was a bit too strong, even IF I happened to be right that there was only a 33% chance of that happening. To clarify, that's not way out there. Rolling a six-sided die will result in a "5" or a "6"   33% of the time, hardly a rare or noteworthy result,

I am very much unconvinced by arguments that 36 out of 36 cases being unvaccinated (and 0% vaccinated) is a "quite high" likelihood, while at the same time it is not unlikely or particular noteworthy if there was another state where 40% of their cases had been vaccinated.

I'm still interested in the percentage of the Minnesota cases, and I don't understand why anyone wouldn't be. Gathering information and studying as I go is part of my learning process, and if that makes me different and awful, well it happens.

And as I said, a highly unusual result may indicate a problem, e.g. bad vaccine batches or that a somewhat vaccine-resistant new mutation has developed. While a "who cares" attitude -- as long as vaccinated cases are still the minority -- may be OK for a message board, I would be horrified if that was the attitude among infectious disease statisticians and professionals.

In my first post in my thread, my motive was to save people time who might be curious about the percentage too -- "As for the Minnesota 20, the article does not give the percentage that were unvaccinated, to save people the trouble of looking for that statistic and not finding."

I'm so sorry that I tried to save people time, or naively assumed that anyone else besides me would care.