At least 14 counties had vaccination rates in 2011-12 below level experts say is needed to protect kindergartners from measles

As concern about the spread of measles from lack of vaccination grows, many Kentucky counties probably have vaccination rates below the minimum that experts say is needed to create "herd immunity" and prevent spread of the highly contagious disease among students in kindergarten.

At least 14 Kentucky counties had measles vaccination rates below 90 percent in the 2011-12 school year, according to state data analyzed by USA Today, in a survey of states that track vaccination rates and make them public. The Courier-Journal published the Kentucky figures in an online database.

The counties under 90 percent were Bath (89%), Boyle (83%), Bullitt (88%), Christian (89%), Harlan (88%), Jefferson (86%), Laurel (85%), Lawrence (88%), Lee (80%), Nelson (82%), Robertson (88%), Rowan (86%), Taylor (82%) and Webster (86%). Data from several counties was not available. For the database with county-by-county figures, click here.

The statewide vaccination rate was 93 percent, pulled down by a rate of 86 percent in Jefferson County, the state's most populous. The lowest rates were 80 percent in Lee County and 82 percent in Nelson and Taylor counties.

Jefferson County officials told The Courier-Journal that the county's rate rose above 90 percent in the last two to three years. Bullitt County school-health coordinator Lesa Bodine told the Louisville newspaper that her data show 94.3 percent of the county's kindergarten students "have been properly immunized," The C-J's Darla Carter reports. "However, she said there are some parents who choose not to immunize their children. She also noted that there can be a delay in receiving proof of vaccination because a child has, for example, transferred from another county or state."

Like many states, Kentucky allows parents to exempt their children from required vaccinations for medical or religious reasons. Measles outbreaks in other states have been blamed at least partly on parents who still believe discredited reports that vaccines cause autism or other disorders. Generally, the stricter the laws, the higher the vaccination rate, Stateline reports. Here's a Stateline map showing how states differ: