[jfengel]

In a world with a low vaccination rate, infection with measles is practically 100%. It spreads more easily than COVID.

You can take your risk with herd immunity if you want. That works well now, with a near universal vaccination rate. But if the rate drops below 90%, then you will get infected.

[somenameforme]

Immunity rate, not vaccination rate. This is why everybody ended up catching COVID, often multiple times, regardless of how much they injected themselves with. Whereas, measles, with an ostensibly higher spread rate, was already on its way out before vaccines were introduced with fewer than 1 new case per 500 people - far below even basic fertility rates. It's because infection with measles is a nice mixture of relatively low risk and providing lifetime immunity. Beyond that, herd immunity is a hand-wavy measurement about statistically preventing perpetual spread within a population, it says much less about individual susceptibility.