21 students at East Bay high school get COVID after attending off-campus event By KTVU Staff article WALNUT CREEK, Calif. - An East Bay high school is grappling with a COVID outbreak that's infected almost 2 dozen students and forced another 100 into quarantine. Twenty-one students at Las Lomas High School in Walnut Creek have the virus, John Nickerson, superintendent of Acalanes Union High School District, said. The explosion in cases was tied to an off-campus event, he said. Nickerson said the students tested positive in the last two weeks of April. "The origin of the cases seems to have been a single off-campus (and non-school) event that the students who tested positive attended or in some cases their siblings attended," he said in a statement. "There does not appear to have been any on-campus transmission of COVID-19."