If you get measles from the MMR vaccine it is not measles it is a vaccine reaction. However, a vaccine reaction is impossible, right? I mean ALL vaccines given at any time for any reason are completely "safe and effective". If you get measles because your mom took you to a "pox party" you are dangerous and evil because you are "unvaccinated" (though afterwards completely and usually permanently immune to measles) but if you get measles because your doctor bullied your mom into a dangerous MMR vaccine, that is A-OK because its just a 'vaccine reaction'?!
https://thevaccinereaction.org/2019/05/children-in-two-states-get-vaccine-strain-measles-from-mmr-vaccine/