Is there evidence linking the Texas measles outbreak to a surge in illegal immigration?

Though Texas health officials have been unable to pinpoint the source of the measles outbreak that began in a Gaines County Mennonite community, there is no evidence connecting it to illegal immigration.

Measles outbreaks typically occur when an unvaccinated person is exposed to the highly contagious virus, and in turn exposes members of undervaccinated communities. A vaccination rate of roughly 95% is required to achieve herd immunity against measles, a level of protection that makes it challenging for infections to spread.

As of the 2023-2024 school year, just 82% of Gaines County kindergarteners were up to date on their measles, mumps and rubella vaccines.

Measles was declared eliminated in the U.S. in 2000, but isolated outbreaks still occur when international travelers return from affected regions to communities with low immunization rates. A 2019 case linked to travel in Israel, for instance, affected a Hasidic Jewish community in New York.