Masks will be required at Raymond High School starting Monday, after nearly two dozen students tested positive for COVID-19 in the days since the school’s homecoming games, bonfire and dance.

David DeRuosi, interim superintendent of Raymond schools, said 23 high school students had tested positive for the virus as of Friday — almost 7% of all the high school’s students. More test results from students with symptoms were still coming in, he said.

The students who are quarantining with a positive COVID case or isolating themselves as they await test results are receiving remote instruction — video-conferencing in to in-person classrooms and receiving course materials online, DeRuosi said.

Cases started popping up after homecoming weekend, DeRuosi said. Masks were recommended but not required at the events, including the dance held indoors.

“As the week progressed, we started to see our numbers go up,” DeRuosi said. “We have been monitoring the situation very closely.”

To slow further spread at school, Raymond High School students will have to wear face coverings, starting Monday morning. Until now, DeRuosi said, masks were recommended, but not required in class and in the halls.

The U.S. Centers for Disease Control and Prevention recommends mask-wearing indoors, regardless of vaccination status.

DeRuosi said the district is not tracking how many students are vaccinated. According to state data, 45% of all residents of Raymond are fully vaccinated, and almost half have received at least one dose of a vaccine. The school district held a vaccination clinic on Friday.