Thousands of students could soon be barred from class because of missing paperwork.
Montgomery County schools report that around 4,200 seventh graders haven't been able to prove they got all their required vaccinations.
Families have until Sept. 15 to prove their kids got their shots or they can't attend school.
New rules went into effect in Maryland this year requiring all seventh graders to be vaccinated for whooping cough and meningitis.
This comes as the county confirms at least 12 students have come down with whooping cough.
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