It has been estimated that about 2 in 10,000 people who get measles will eventually develop SSPE

Depending in your view, thats not a really low chance. Since we’re talking of a chance to die - I’d say it’s high.

However, a 2016 study estimated that the rate for unvaccinated infants under 15 months was as high as 1 in 609.

Oops - kids at school are older, but these numbers are way higher… Let’s just run both and see what happens. I don’t have enough data, to do some “real math” but someone mentioned about 100 students being at risk of getting infected as they’re unvaccinated. Lets just assume all of them get infected.

First: 2 in 10000 will develop SSPE, that means 9998 in 10000 won’t. For 100 students: (9998/10000)^100 = 0.98 so, a 98% chance, that no-one is affected and tha lt means a 2% chance, that at least one is affected by SSPE.

Second number: 1 in 609 means, that 608 in 609 won’t. For 100 students: (608/609)^100 = 0.85 so that’s an 85% chance that nothing happens and a whopping 15% chance that at least one student develops SSPE.

I know this math I likely not near reality, but damn.