Letters went home with 220 students Wednesday regarding their exposure to students who were infected with pertussis, school system spokesman Stephanie Knott said. Parents were informed that the Orange County Health Department had ordered the students to take a course of antibiotics to protect themselves from the disease.

Students would be excluded from school for 21 days beginning Monday if they did not obtain the antibiotics.

Monday, nine of the 220 students were absent, Knott said. Their families said they were scheduling appointments and obtaining prescriptions so the students could return to school Tuesday. No one refused to obtain prescriptions, Knott said.