Project reveals asymptomatic spread of COVID-19 in schools

A pilot project in the Omaha Public School district detected new SARS-CoV-2 infections which wouldn’t have been detected otherwise, indicating that infection and case rates in schools are much higher that what’s being reported through routine self-initiated tests and reporting. This study is believed to be the first description of SARS-CoV-2 testing in K-12 schools that combines individual screening with building-level environmental monitoring.

Infection rates detected by the OPS PROTECTS program, in a partnership with UNMC, were two-and-a-half times higher for staff and nearly six times higher for students than what was routinely observed. Additionally, the project found almost 10 times the cases per population than what was observed through community testing in the surrounding county.

“This data shows the prevalence of SARS-CoV-2 infection in school-aged children is being dramatically underestimated,” said Jana Broadhurst, MD, PhD, corresponding author on the study. “We were able to identify and remove staff and students from the school environment who wouldn’t have otherwise been identified. This kind of rigorous infection control and environmental monitoring not only helps lessen risk during school operations, it also might provide insight into how much a disease is spreading in a community where access to testing is limited.”

OPS PROTECTS was conducted in three schools in November and December of 2020 in an area that is predominantly of minority race and ethnicity and experiences poverty. The project screened students and staff without symptoms via a weekly PCR test of saliva, along with environmental air, surface and wastewater testing. Nearly 100% of the teachers and staff in the schools took part; 12% of students participated. During the pilot period, OPS was using a hybrid attendance model to decrease classroom density, with about one-fourth as many students present each day compared to a typical school year.

“It’s extremely gratifying to take part in a project which reinforced the importance of some of the measures we put in place across the school district,” said Cheryl Logan, Omaha Public Schools superintendent. “This study shows how things like wearing masks, reducing student density and improving air exchange systems can decrease COVID-19 transmission in schools.”

Environmental sampling consistently found the presence of SARS-CoV-2 in the wastewater streams of the schools. Positive air and surface samples were also found, but only in two rooms total.

“We believe this project represents a feasible, scalable and novel approach to screening and monitoring in a school setting,” Dr. Broadhurst said. “Our results show as many as nine in 10 student COVID-19 cases and seven in 10 staff cases might be missed by conventional reporting. Doing this kind of testing can help lessen transmission in schools because of the ability to better isolate, trace and manage school activities.”