Ninety out of the 600 attendees at a recent California high school prom tested positive for COVID-19.

According to KGO-TV, students at San Mateo High School gathered for the prom at San Francisco’s Asian Art Museum. Masks were optional for the event, which organizers said followed Centers for Disease Control and Prevention guidance.

While many schools canceled proms in 2020 and 2021, San Mateo High, like many schools across the U.S., decided to hold a 2022 prom amid the pandemic.

“This has been a really hard year for kids and we need to keep having as many activities as we can,” Kevin Skelly, district superintendent, told KGO.

Because of this outbreak, however, Skelly said further events will need additional precautions.

"We're going to be more careful about activities. We're going to test more students beforehand to make sure they're not going into the dance COVID positive,” Skelly said.

The district said none of the students are experiencing severe symptoms.

Some students say despite the outbreak, attending prom was worth it.

"Overall, I think it was worth it. It was a great, fun time,” student Parker Del Balso told KGO.