(CNN)Nearly 300 Florida high school graduates and their families have been told to quarantine after an attendee at their graduation ceremony was diagnosed with the coronavirus.
Bayside High School in Palm Bay, Florida, held an outdoor graduation ceremony for seniors last Saturday, an event that appeared to mostly adhere to coronavirus safety guidelines.
However, someone who attended the event tested positive for the coronavirus shortly after the ceremony, said Anita Stremmel, assistant director of the Florida Department of Health in Brevard County. The school district informed the health department, which confirmed the result in a lab test.
As a precaution, the health department told parents their children need to "quarantine at home for 14 days from their last day of attendance at the facility," according to a letter from the department obtained by CNN.
Parents and close contacts of students who may have been exposed were advised to quarantine themselves at home and monitor themselves for symptoms, too, the health department wrote in the letter.
The school district created a safety protocol for in-person graduations. Footage the school shared of the event showed students outdoors on the school's football field, seated several feet apart. They wore masks, and so did attendees in the bleachers.
The health department didn't confirm whether the person who tested positive for coronavirus was a student or adult. Students were granted two guests each, and about 30 adult school and district staff were present at the event, Brevard County Public Schools spokesperson Nicki Hensley told CNN.
Faculty wearing gloves and masks handed students their diplomas as they walked across the stage. Only speakers removed their masks when they took the podium. Students formed small groups when the ceremony ended.
Florida continues to set new records in coronavirus cases and deaths as the state passes 450,000 cases. Over 6,300 residents have died, and this week, child coronavirus hospitalizations rose 23%. The state has maintained that schools must reopen for in-person instruction, though many districts have given parents the choice to opt out so their students can learn online.