Over 700 COVID-19 cases over just five days in one high school district. Staffing shortages. During the first week back from winter break, local schools began to report record numbers of COVID-19 cases among students and staff amid the emergence of the highly contagious omicron variant.

Late last week, San Mateo County amended quarantine and isolation guidelines to align with the new, more lax, Centers for Disease Control and Prevention guidelines, which will result in shorter absences from school if someone tests positive or is exposed to the virus, which could help alleviate staffing challenges schools are facing.

The Sequoia Union High School District, which has roughly 11,000 students and staff members, reported a startling 710 cases its first week back (from Jan. 3 to 7). Prior to winter break there were only about 175 cases in total during the entire fall semester. The district updates its COVID-19 data dashboard every weekend.

Of the cases last week, 76 were among staff members, while 634 were among students. At Menlo-Atherton High School there were 177 cases (11 were staff). At Woodside High School, there were 162 cases (10 were staff). At TIDE Academy in Menlo Park, there were 19 cases (three were staff).

"Once again, our country has been shaken by COVID-19 and its impact. While the country is paying close attention to omicron’s next move, educational leaders are staying abreast of health updates and putting systems in place to support the safety of students and staff," Superintendent Darnise Williams said in an email to families on Friday. "Our team has been working to address many concerns related to safety, testing, school closures, and staffing. I have responded to many emails and made phone calls in an attempt to allay fears around possible school closures and to reiterate the district’s commitment to maintain safe spaces for staff and students. Our goal is to keep schools open for in-person instruction."

M-A Principal Karl Losekoot told families in a Sunday email that "there is no doubt that this has been a strange week as we are existing amidst the omicron surge."

The school is restricting fans of indoor sports to "just immediate family members" for the time being, he said. The school will reevaluate weekly, looking at new cases of infection in the school and broader community, he said.

On Thursday, KN95 masks were passed out to staff members and students, Losekoot said and the district will be ordering more. Health officials have advised people to upgrade from cloth face masks to N95 respirators since omicron appears to be more contagious than previous variants.

There were 85 cases reported in the K-8 Ravenswood City School District from Jan. 3 to 7, which has about 1,501 students enrolled in its non-charter schools in Menlo Park and East Palo Alto. The district does not report cases in its charter schools, which it doesn't operate and enroll about 1,250 students. Costaño Elementary School reported the most cases (27), while Los Robles-Ronald McNair Elementary School reported the fewest (eight). Seventy of the cases were among students, while 15 were among staff.

In previous weeks, the district reported case numbers in the single digits.

From Jan. 3 to 10, there have been 45 cases reported in the Menlo Park City School District, which has about 2,716 students at its Atherton and Menlo Park campuses. The district does not break down how many of the cases were among staff and how many were among students.

The two-school, 1,099-student Las Lomitas Elementary School District has reported 47 cases since the semester began last week.

The Portola Valley School District reported 26 cases between its two schools during the week of Jan. 3. They were fairly evenly split, with 12 of those cases at Ormondale Elementary School and 14 at Corte Madera Middle School.

There were six cases reported in the 365-student Woodside Elementary School District last week Superintendent Steve Frank credited the district's distribution of rapid tests to families before returning to campus from winter break with catching 17 cases.

New quarantine guidance

Staffing has proved a challenge, some districts moved to shorten the quarantine guidance for teachers and other staff who test positive, allowing them to return to the classroom more quickly.

On Jan. 6, the county adopted the state’s new quarantine guidelines, which state that if fully vaccinated — meaning it's been at least two weeks after having received two doses and a booster (if booster-eligible) — students or staff members who are exposed to someone who tests positive for the virus can attend school as long as they are asymptomatic, get tested five to seven days after the exposure, and continue to monitor for symptoms.

Staff members who aren't fully vaccinated and test positive can return to campus after five days, if they don't have symptoms and test negative on the fifth day. Previously, people who tested positive needed to quarantine for 10 days.

Students who aren’t vaccinated are required to quarantine for at least five days following the date they were last exposed to COVID-19. If they test negative on or after day five, or have no symptoms, they can return to school.

Decisions about school closures will be made by the schools and districts, in consultation with the county health department, but the state has made clear that there are no thresholds. "The process should be guided by local epidemiology, with particular attention paid to concern for in-school transmission. Operational factors may also be considered, including the ability to maintain sufficient teaching staff to provide in-person instruction," according to state guidance.

"A temporary school closure due to COVID-19 should be a last resort and considered only after all available resources have been exhausted in an attempt to preserve in-person education," according to the guidance.