The latest measles case, identified Monday, means adults who only got one of the two necessary vaccinations as children are vulnerable to the virus, which has infected 21 people in Tarrant and Denton counties since Aug. 15, The Dallas Morning News reported Monday.
"This worker is one of those we believe had only gotten one shot as a kid," said Russell Jones, chief epidemiologist for the Tarrant County Public Health Department. "One shot will not give you complete immunity from the measles because it's so infectious. You need two shots to cover you 100 percent."
"People who [have] already graduated from high school probably missed the second shot," Jones added. "If they are healthcare workers or traveling abroad, they need to get that second shot."
So far, all 21 cases can be linked to the Eagle Mountain International Church in Newark, Texas, health officials said.