Texas health officials confirmed the state’s worst outbreak of measles in nearly 30 years is concentrated in a “close-knit, undervaccinated” Mennonite community in Gaines County.

As of Feb. 18 cases had more than doubled to 58 — mostly in children and teens — and 13 people had been hospitalized. Those who are infected are either unvaccinated or their vaccination status is unknown.

Gaines County is home to a significant number of Low German Mennonites in the Seminole area and has one of the highest rates of children who opt out of at least one required vaccine. Texas law allows children to get an exemption from school vaccines for reasons of conscience, including religious beliefs.

“The church isn’t the reason that they’re not vaccinated,” said Texas Department of State Health Services spokesperson Lara Anton, who noted many families send their children to small private schools or are homeschooled. “It’s all personal choice and you can do whatever you want. It’s just that the community doesn’t go and get regular health care.”

Die Mennonitische Post, a German-language newspaper serving Mennonites throughout the Americas, included a letter in its Feb. 21 edition written Johann and Katharina Neustädter of Seminole that reported, “Oh yes, there are a lot of sick people here. Many have fever or diarrhea, vomiting or measles. Also headaches and colds. That’s not good.”