COVID-19 cases are cropping up at local public school districts which have reopened classrooms to students over the last two months, and some districts are beginning to update case counts on their websites.

The Menlo Park City School District has reported 10 cases of COVID among staff members and students on its website since students returned to campus on Sept. 28). About 2,330 of the district's 2,808 students have returned to campus thus far, said Parke Treadway, the district's public information officer.

Four cohorts of students have moved to distance learning for 14-day quarantines. Not every case requires a cohort to move, either because the infected person didn't have close contact with a cohort or had not been with their cohort within the close contact period, Treadway said. According to the Centers for Disease Control and Prevention, close contacts are those who were in proximity within two days of test specimen collection or onset of symptoms.

"Our week on/week off model is really helping limit the number of close contacts, as we had hoped," she said. "We have not had multiple cases within the same cohort."

The district is including the positive COVID-19 case data for the public in an effort to be transparent, she said. "That is important to our board and leadership."

District officials update the previous week's data by Tuesday, and positive cases are reported to San Mateo County Health. Case notifications are provided to the appropriate cohorts and school communities, but no identifying details about individuals testing positive will be provided to the public.

San Mateo County schools must halt stop in-person learning if:

• There are multiple confirmed cases in multiple cohorts within 14 days on a single campus

• 5% or more of the total number of teachers, students, and staff on a campus are confirmed positive cases within a 14-day period, depending on the size and physical layout of the school

• There is insufficient staffing is available because of health or the need to quarantine

So far there have been no cases reported in the Portola Valley School District, which reopened to students in October and has a COVID-19 case dashboard on its website. So far, almost 250 students in grades TK-5 of the district's roughly 495 students have returned to campus, according to a presentation by district staff.

"We will post the COVID data on our website to assist parents, staff, and the community in understanding the degree to which PVSD is directly experiencing COVID positive cases over the course of time, which will be updated weekly," said Superintendent Roberta Zarea in an email.

There have been no cases reported in the Las Lomitas Elementary School District since it reopened last month, said Superintendent Beth Polito. The district has two schools: Las Lomitas Elementary in Atherton and La Entrada Middle School in Menlo Park. District officials plan to create a similar public reporting matrix soon, she said.

In the nearby Palo Alto Unified School District, six cases — four staff members and two students — have been reported since its schools reopened in August to elementary school students, according to the district's website.

The Woodside Elementary School District, which reopened to students in October, has reported no COVID-19 cases in the 369-student district.