Pooled testing for SARS-CoV-2 surveillance in schools: evaluation of transmission control, testing resources, and educational disruption

Pooled testing programs were introduced during the COVID-19 pandemic to expand surveillance capacity while preserving testing resources. However, evidenceCE: Abstract is not matching with the original source. Please verify. on their epidemiological impact in schools remains limited.

We analyzed data from the pooled testing program implemented in 62 primary schools in Basel-Landschaft, Switzerland, during the Fall-Winter 2021 Delta wave. We fitted an agent-based transmission model informed by pooled and individual testing results, school characteristics, contact networks, and community incidence to pooled positivity ratios in four administrative areas with similar epidemic trajectories. We compared pooled testing with alternative protocols in terms of school transmission, testing volume, and student-days lost.

Pooled testing was offered to 21'187 students, with consistently high participation (71-79%). The model reproduced observed pool positivity trends well. In-school transmission was estimated to be 50%-87%, 63%-104%, and 72%-133% higher under reactive class closure, reactive, and symptomatic screening respectively, compared with pooled testing. Weekly individual screening was estimated to achieve similar reductions while requiring 15-25 times more tests. Model-based estimates also indicated that relaxing class closure after depooling substantially would reduce student-days lost without increasing transmission.

During the Fall winter Delta wave of 2021, pooled testing effectively reduced SARS-CoV-2 transmission in primary schools while remaining resource-efficient. Combining early detection of asymptomatic infections with low testing demands, pooled testing offers a scalable approach to school surveillance and preparedness, providing a framework that can be further evaluated across respiratory pathogens and epidemiological contexts.