Parents have traditionally worried about their kids drinking alcohol, doing drugs, or getting pregnant at their high school prom. But this year at San Mateo High School, it turns out parents had other concerns to worry about.

Of the 600 attendees at the prom held at San Francisco’s Asian Art Museum on April 9, 90 had confirmed positive tests for COVID-19 in the days following. That's 15% of the attendees.

San Mateo Union High School District Superintendent Kevin Skelly tells ABC7 that all of the COVID cases were mild.

"This has been a really hard year for kids and we need to keep having as many activities as we can," Skelly said, by way of an explanation.

Whereas some other schools in the area required masks at prom, this particular dance did not. The president of the San Mateo High School Parent-Teacher-Organization, whose child got COVID at the dance, pointed out that the decision not to require masks was in line with San Francisco’s health guidance, as well as the CDC's.

"You have to just weigh 'are we willing to sacrifice what will happen if you do get COVID and you have to quarantine' versus 'is it worth it just to go out and have a good time for something you can do only twice in your life really,'" PTA President Sandi Del Balso told ABC 7.

San Mateo High School had already had a COVID outbreak this year. That school and a few others in the district had outbreaks the way many schools did in January, but things had leveled off for the past couple of months. The week before Spring Break, only one student in the entire district tested positive, and that student was at San Mateo High.

By April 4, the school had six kids who tested positive. On April 11, two days after prom, 83 kids at San Mateo tested positive. The school with the next-closest number of cases in the district had just six.

Skelly says other schools within the San Mateo Union High School District are planning for stricter safety protocols at their proms in response to what happened at San Mateo High. That will include testing more students beforehand to ensure they aren’t infecting people at the dance.

Top image by Zedla/Wikimedia