MIAMI (CBS4) – More than 20 percent of kindergarteners in Miami-Dade County lacked complete immunizations in the previous school year, the highest percentage of Florida’s 67 counties, according to a new report.

Kids without the required vaccinations are allowed to go to class under a provisional status.

READ MORE: Fort Lauderdale Man Accused Of Sexually Assaulting Teen Girl

CBS4 news partner the Miami Herald reports that in Miami-Dade, only 76.7 percent of kindergarteners had complete immunizations in 2010-11. In Broward, the percentage was 92.9 percent; in Palm Beach it was 90.4 percent, and in Monroe County, 93.6 percent. Statewide, 91.1 percent of public school children began kindergarten in the last school year with complete immunizations.

READ MORE: Housing Crisis: County Mayors To Hold Roundtable On Skyrocketing Rents

Officials don’t know why Miami-Dade’s vaccination rate is so low, but they’re concerned that the low rate puts students and their communities at higher risk of catching measles, mumps and whooping cough.

MORE NEWS: 'Ride Of Silence' To Raise Awareness For Cyclists Safety On The Road

(TM and © Copyright 2011 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2010 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)