Depends on your assumptions. Measles requires 92-95% immunity for hers immunity. Here's a likely scenario for a K-5 school of 600 children, 100 per class, assu

Depends on your assumptions. Measles requires 92-95% immunity for hers immunity. Here's a likely scenario for a K-5 school of 600 children, 100 per class, assume incoming post requirement drop is 1/5 students: Year 0: 96% immune (Typical from what I can glean online) Year 1: 80% of Ks now immunity from vaccination. 96% of 1-5 immune as normal. Non immune =20 +5*(4) = 40 out of 600, or 7% of 600 kiddos. So 93% rate of immunity. Right on the bubble in a year's time. Tweak numbers as you'd like, but with even modest decreases (16% loss, or and additional one in 6 hesitancy) in vaccination, Measles herd immunity is tettering in a year and lost in the second year, by a large margin