A new study finds four counties in Florida are some of the most vulnerable areas for a measles outbreak in the nation.
Miami-Dade County is most-at risk in the state, ranking third in the nation. Broward is seventh, Orange is 14th and Hillsborough is 17th.
The study was produced by researchers at Johns Hopkins University and the University of Texas at Austin.
It comes as the United States experiences one of the worst years for measles since 1994 and since the disease was eradicated from the country in 2000.
"We all knew that what was really driving the return of diseases like measles was the growing vaccine refusal, the anti-vax movement," said UT Austin professor Sahotra Sarkar.
"And what's driving a lot of the risk in Florida is not only a slightly lower vaccination rate but also the number of international travelers coming in," he explained.
Sarkar said while it’s good that Florida doesn’t allow philosophical exemptions from vaccines like some other states do, it still allows religious exemptions, which can also factor into higher risk levels.
The Centers for Disease Control and Prevention has so far reported more than 800 cases of measles nationwide this year.
Two were in Florida, the first in Broward and the second in Pinellas. Both individuals had recently travelled overseas.
According to the study, China, India, Japan, Mexico, the Philippines, Thailand and Ukraine pose the greatest measles risk.
Sarkar suggested if the national outbreak worsens, the country should consider requiring anyone who travels to or from those countries to prove they have received the measles, mumps, rubella (MMR) vaccine. Similar requirements are in place for travel to areas prone to yellow fever.
The Florida Department of Health urges all residents to get at least one dose of the MMR vaccine, and recommends international travelers, health workers and people with weakened immune systems get an additional dose.