Effectiveness of a 4x10 Surveillance Program to Detect and Prevent SARS-CoV-2 Transmission in a Public Primary School in a Marginalized Community of San Luis Potosi, Mexico

Background: Mexican schools closed down in-person operations due to COVID-19 from March 2020 to February 2021. According to World Bank models, this implies a loss of 0.9 years of schooling. We set forth to design a COVID-19 safe return to school program specially adapted for both low national SARS-CoV-2 testing levels and a virtually non-existent school children vaccination scheme.  Methods: The Community Program for a Safe Return encompassed five strategies: i) Community Surveillance (SARS-CoV-2 RT-qPCR testing of a community); ii) COVID-19 Education; iii) Hybrid Learning Strategy (dividing a classroom into two weekly-alternating groups of in-person schooling; iv) Layered Protection (health-status questionnaire, body-temperature control, mandatory facemasks, increased classroom ventilation, physical distancing and routine disinfection of classrooms) and; v) Virus Surveillance (weekly RT-qPCR testing of students and staff).  Findings: A pilot program was implemented in a community of San Luis Potosí having a SARS-CoV-2 positivity rate below 5%. Negative SARS-CoV-2 test results were maintained in both children and staff throughout the study period. Interpretation Both WHO and CDC have emphasized the priority of in-person learning for students. Our program proved capable of providing a COVID-19 safe return to school and had an additional, unexpected, benefit of increasing community awareness and increased suspect-case surveillance. Such community involvement allowed for tailored adaptations of school attendance to be made, a strategy that proved to be both economically and epidemiologically feasible for resource limited settings. Funding: This study was supported by COPOCYT-CEEPAC/CTF/136/2020, FID 18397 Declaration of Interest: We declare no competing interests. Ethical Approval: Our study was reviewed and authorized by the State Health Ministry Committee of Bioethics (SLP/07/2020).