Authoritarian cdc says it’s so, so it must be so, but it isn’t.
"CDC considers people who received two doses of measles vaccine as children according to the U.S. vaccination schedule protected for life, and they do not ever need a booster dose," according to the CDC.
https://www.newsweek.com/measles-immunization-vaccine-immune-schedule-1403860
And yet the measles vaccine failure rate for 2 doses is around 50%.
https://www.nvic.org/vaccines-and-diseases/Measles/measles-vaccine-effectiveness.aspx
And in fact many of the outbreaks are among the fully vaccinated.