NORTH TEXAS (CBSDFW.COM) – A new study looking at vaccination exemptions for children named both Tarrant and Collin Counties as “hot spots,” potentially vulnerable to an outbreak of diseases like the measles.

Texas is one of 18 states that allow parents to opt out of shots for their school-age children for non-medical reasons. A study by the Public Library of Science Journal of Medicine looked at the areas with the highest exemptions. Among them: both Tarrant County and Collin County – specifically, Fort Worth and Plano.

At least 518 Tarrant County Kindergarteners in 2015-2016 were not vaccinated, according to the study. Nearly 60,000 Texas children are not, according to state health data.

A measles outbreak in Ellis County earlier this year sickened at least six people.

Terri Andrews, president of the Immunization Collaboration of Tarrant County says it could happen in other parts of the state this year as well.

“It is scary to see the rise in exemptions,” she says. “What we’re doing as a collaboration and in Texas is everyone is trying to be pro-active so that we can encourage people on social media to read good information about vaccines.

CBS 11 News reached out to Texans for Vaccine Choice about the study. Executive Director Jackie Schlegle says, “Ultimately, parents are looking for facts to make informed decisions. We ought to put all the facts on the table and let them make those decisions with their chosen medical providers.”