St. Louis County Health Department officials will offer HIV tests at Normandy High School later this month after a public health inspection determined that several of its students may have been exposed to HIV, the St. Louis Post-Dispatch reports.

According to the article, the school’s 1,300 students were sent home on Monday, October 13, with letters advising their parents to talk to them about getting tested if they have had unprotected sex. A week earlier, an HIV diagnosis was traced to students at the school.

“There is concern, but we really don’t want to raise alarms here,” said health department spokesman Craig LeFebvre. “This is not some major new outbreak or method of transmission, and there’s no evidence to suggest it was deliberately being spread.”

The Post-Dispatch reports that about 5 percent of people who test HIV positive in the St. Louis region are diagnosed as teenagers.