Digital COVID-19 symptom screening and SARS-CoV-2 testing through RT-LAMP saliva of students and asymptomatic employees in a public school in Brazil

Abstract

Children were the last that were vaccinated during the COVID-19 pandemic. In this scenario, schools were the site of amplification and spread of COVID-19 and new variants during the pandemia. Objective: To evaluate a respiratory symptoms screening system and test asymptomatic individuals (high school students and employees) at a public school in Brazil. Methods: An online COVID-19 symptom surveillance platform was implemented for employees and students answered a questionnaire by mobile phone and/or website before going to school. Symptomatic individuals were referred to primary care unit. SARS-CoV-2 reverse transcription loop- mediated isothermal amplification (RT-LAMP) of saliva samples was performed weekly. The test cost was estimated. Results: A total of 969 samples were tested (mean of 108 tests per week). A professor was symptomatic and tested positive during the study period. However, no asymptomatic participants tested positive for COVID-19, and no cases of SARS-CoV-2 transmission occurred at school despite the high transmissibility of the Delta variant, the local predominant variant at the time of the study and several outbreaks that occurred in public schools in Brazil. The average cost of our test was $13,6 per test. Conclusion: Implementation of an online system of COVID-19 respiratory symptom screening and testing SARS-CoV-2 through saliva in asymptomatic individuals is a feasible, low-cost and practical option to be used, especially in low-income countries.