RALEIGH, N.C. -- Schools across the state have suspended hundreds of sixth graders with outdated vaccination shots in compliance with a new state law, while many other students face suspension, school officials said Friday.

Principals and other school staff are calling parents directly who have not updated immunization records for their child. A law passed by the General Assembly in January requires children to have one booster dose of tetanus-diphtheria-pertussis, or Tdap, if five years have passed since their last one. The information warns parents that their child can be suspended if immunizations aren't up to date within 30 days of starting school. The rules apply to about 210,000 students.

Most districts had deadlines throughout this week and began suspending students Wednesday.

The Centers for Disease Control and Prevention recommended the booster after North Carolina saw an increase in pertussis, or whooping cough, said state Department of Health and Human Services spokeswoman Amy Caruso. The requirement took effect for the 2008-09 school year.

On Thursday afternoon, 1,150 sixth-graders in Guilford County Schools still needed to submit proof of their vaccination.

"There was a free clinic last night so I'm sure that number has probably gone down a lot," said Guilford County Schools spokeswoman Jennifer Landes.

Landes said about 5,400 sixth graders are in the county's public schools system.

Winston-Salem/Forsyth County Schools had to suspend over 100 of their 3,800 sixth graders despite informing parents of county clinics. Social workers and school nurses are working with individuals now, said school spokesman Theo Helm.

"Sometimes no matter how many things we send home, some parents don't hear the message," said Helm.

About 1,200 Charlotte-Mecklenburg County middle school students hadn't updated their records by Thursday. A spokeswoman said that most of those students were those who didn't have a Tdap shot.

"If our parents brought in proof of an appointment or updated records, their children were allowed to stay in school," said spokeswoman Cynthia Robbins.

The school district has also paired with the Mecklenburg County Health Department to offer free Tdap booster clinics. To find out more, visit the CMS Web site.

Buncombe County Schools have extended their deadline because of the gas shortage in the western part of the state.