As a measles outbreak centered in West Texas continues to grow, a new poll finds that a growing share of adults in the United States have heard false claims about the disease and the vaccine to prevent it – and many aren’t completely confident in their conviction.

Texas is experiencing its largest measles outbreak in 30 years. The virus has infected more than 600 people and killed two school-aged children.

The Texas health department reported 624 cases of measles in the state on Tuesday, an increase of 27 from April 18, as the United States battles one of its worst outbreaks of the childhood disease. Cases in Gaines County,