COVID-19 early detection system examined in UC San Diego and San Diego County colleges

To help schools reduce the risk of COVID-19 outbreaks when they return to face-to-face classes, the University of California, San Diego, and County of San Diego are testing the Safer at School early warning system, an evidence-based detection program SARS-CoV-2 in schools and day care centers.

Modeled on UC San Diego’s Return to Learn, a unique approach to safely resuming teaching, learning, and research at a university, Safer at School’s early warning system is scaled to individual schools and daycare without the resources available to a research university. The Safer at School Early Alert tests the presence of coronavirus particles through daily wastewater and surface monitoring. Combined with a responsive testing strategy, the goal is to quickly identify children or employees infected with COVID-19 before an outbreak occurs.

To help schools reduce the risk of COVID-19 outbreaks upon resumption of personal teaching, the University of California at San Diego and County San Diego are testing the Safer at School early warning system, an evidence-based program to detect SARS- CoV-2 in schools and day care centers. Safer at School Early Alert tests the presence of coronavirus particles through daily wastewater and surface monitoring. Combined with a responsive testing strategy, the goal is to quickly identify children or employees infected with COVID-19 before an outbreak occurs. Further information on the early warning system Safer at School (SASEA), a COVID-19 pilot program for wastewater detection for K-12 schools and day care centers, can be found at

Ten TK-8 schools in San Diego county and two daycare centers are participating in this SARS-CoV-2 screening program, funded by San Diego County and designed by UC San Diego.

When Vista Grande Elementary School began offering a hybrid classroom model that encompasses 50 percent of personal classroom capacity, they implemented public health guidelines, including daily symptom screening, social distancing, and requiring all students and staff to wear masks.

Headmistress Tita Cordero-Bautista and David Miyashiro, EdD, Superintendent of the Cajon Valley Union School District, advocated a safe school environment for all and wanted to do more to enroll the campus in Safer at School Early Alert.

“The health, safety and wellbeing of our employees and students are our top priority. Our educators use every resource at their disposal to nurture an engaging learning experience that is filled with rigor. However, we understand that distance learning is not ideal for every student or family, ”said Cordero-Bautista.

“Many in our community are at high risk for COVID-19. By participating in the Safe School Attendance early warning system, we want to allay concerns about school safety so that parents and students can feel comfortable in school while building meaningful relationships and learning. “

As part of the surface monitoring step in the early warning program, Tamara Jerjees, assistant at Vista Grande Elementary School, uses a swab to scan a 1 square foot section of the center of the floor in a classroom where aerosols appear to settle. Photo credit: San Diego County

Every third adult infected with SARS-CoV-2 shows no symptoms of COVID-19, but can continue to spread the virus. The virus can be detected on surfaces and in human feces. Even those with no symptoms will shed the virus in their feces and breathe it into the air, where it then settles on surfaces.

Return to Learn positions UC San Diego as the nation’s leader in COVID-19 detection and mitigation. Daily screening, masking, physical distancing, weekly asymptomatic student testing, and daily wastewater monitoring are key elements of the university’s broader strategy to gradually repopulate its campus. Because of the effectiveness of Return to Learn, UC San Diego is one of the few large colleges in the country with a large student body on campus and a low infection rate.

“Many universities conduct testing, contact tracing, and face-covering, but what sets UC San Diego apart is our data-driven, adaptive, and comprehensive approach,” said Pradeep K. Khosla, Chancellor of UC San Diego. “Return to Learn has helped us successfully identify and manage the presence of viruses on our campus. We learned a lot to develop this approach. We want to share this knowledge with others to promote better health outcomes in school systems and in communities everywhere. “

Rebecca Fielding-Miller, PhD, MSPH, Assistant Professor at the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego, leads a design team led by the science and expertise of her peers, the Return to Learn have developed a simple test model that can be implemented at any school.

Safer at School Early Alert is being tested in communities at highest risk for COVID-19, including San Ysidro, Chula Vista, El Cajon, Southeast San Diego, and Vista. These communities primarily serve low-income families and migrants who have greater difficulty accessing COVID-19 testing and may have increased levels of vaccine reluctance.

“The Safer School Early Warning System is currently in the validation phase to understand how accurate these monitoring systems are in day care centers and primary schools. But there is another important point that happens after we get a positive signal for SARS-CoV-2, ”said Fielding-Miller, the lead investigator. “Residents in the hardest-hit communities are often reluctant to test for COVID-19. That’s why we’re working with these communities to understand how to make testing safe and accessible. Because a signal that is triggered without a test is like a fire alarm that is triggered without a fire extinguisher. It’s not useful. It’s just scary. “

The program includes elements of risk reduction, virus surveillance and a strong focus on public health interventions that work for each community.

“The safe reopening of schools remains a priority for the County of San Diego,” said Dr. Wilma J. Wooten, MPH, San Diego County Health Officer. “What UC San Diego showed with the Safer at School Early Alert pilot program models the types of steps that can help us get back into class while continuing to fight the virus.”

The Safer School Early Warning System contains three elements. The first involves technology introduced at UC San Diego to collect daily wastewater samples that are tested for flakes of the coronavirus in the laboratory of Rob Knight, PhD, professor of pediatrics at the UC San Diego School of Medicine. A robot installed at each location collects wastewater samples so that the researchers can detect SARS-CoV-2 three to five days before the individual tests. Childcare centers also send used diapers to test stool samples in children who have not yet been potty trained.

Vista Grande Elementary

Vista Grande Elementary School implemented safety protocols, including wearing the mask and keeping the space between students’ desks. The Safer School Early Warning program provides an extra layer that school officials say they have peace of mind. Photo credit: San Diego County

A second step includes daily surface monitoring. Teachers or staff members use a swab to scan a 1-square-foot section of the center of the floor in a classroom where aerosols settle. These samples are tested daily in UC San Diego’s EXCITE (Expedited COVID Identification Environment) laboratory.

Testing children and employees at each location is the third part of the detection program. Children and employees who voluntarily consent will be subjected to free COVID-19 tests in their school or daycare center in order to respond to a positive result of the sewage or surface monitoring.

When a child gets a nasal swab for the first time, they can be nervous, Fielding-Miller said. To address her concerns, a team of certified nursing assistants walk the children through the process every step of the way to ensure they are in complete control of what is happening, she said.

“We tell the kids that it’s a very thorough nose pick. One of our testers says, “I’ll just chase your boogers around for a second,” said Fielding-Miller.

Should a person test positive for COVID-19, the person or parent will be informed and instructed to consult a doctor. The school will also be notified so administrators can initiate exposure protocols.

In accordance with federal and state regulations, San Diego County Public Health will be notified of positive cases. Participant privacy is a priority. Only doctors and researchers, and public health officials who need to know the identities of those who test positive for SARS-CoV-2, have access to identifying information.


In addition to surface monitoring, a robot takes wastewater samples every 30 minutes to determine the presence of SARS-CoV-2 on every campus. Photo credit: San Diego County

The program currently processes 1,000 anterior nasal swab tests per week. Researchers at UC San Diego developed a rigorous virus testing program designed to detect potential outbreaks as early as possible. The tests are carried out in the EXCITE laboratory at UC San Diego. The test results are compared with the results of the sewage and surface monitoring systems to validate the program.

Should the sewage or surface monitoring result in a positive result, children and staff at the school or childcare center will be given a COVID-19 test as soon as possible so that the person (s) who may be carrying the virus and their close contacts can have Quarantine can be used to stop an outbreak.

“Our goal is to develop a package of interventions that can be implemented across the county, across the state, or even across the country,” said Fielding-Miller. “We have heard from many of our school partners that the program makes them feel good and safe because there is an additional level of surveillance on their campus.”

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