Measles is a special case in terms of infection. There is a line of thought that exposure simply cannot be stopped, that immunization or inevitable infection are the only options. It is a truly airborne disease. If someone with measles coughs in a room and walks away, people walking through that room an hour later will be infected. The standard for social-distancing for measles wouldn't be 6 feet. It would be something like 600 feet, preferably upwind. I read once about the cleaning standard for clothes or objects exposed to measles. Not bleach. Fire. Lots of fire.

Measles in the past was endemic. Everyone got it at some point. Most survived and so the population was somewhat resistant. But today? Without that resistance it would spread through any unvaccinated population like something from a hollywood movie.