Sentinel Cards Provide Practical SARS-CoV-2 Monitoring in School Settings
Victor J. Cantú,
Karenina Sanders,
Pedro Belda-Ferre,
Rodolfo A. Salido,
Rebecca Tsai,
Brett Austin,
William Jordan,
Menka Asudani,
Amanda Walster,
Celestine G. Magallanes,
Holly Valentine,
Araz Manjoonian,
Carrissa Wijaya,
Vinton Omaleki,
Stefan Aigner,
Nathan A. Baer,
Maryann Betty,
Anelizze Castro-Martínez,
Willi Cheung,
Peter De Hoff,
Emily Eisner,
Abbas Hakim,
Alma L. Lastrella,
Elijah S. Lawrence,
Toan T. Ngo,
Tyler Ostrander,
Ashley Plascencia,
Shashank Sathe,
Elizabeth W. Smoot,
Aaron F. Carlin,
Gene W. Yeo,
Louise C. Laurent,
Anna Liza Manlutac,
Rebecca Fielding-Miller,
Rob Knight
Affiliations
Victor J. Cantú
Department of Bioengineering, University of California San Diego, La Jolla, California, USA
Karenina Sanders
Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Pedro Belda-Ferre
Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Rodolfo A. Salido
Department of Bioengineering, University of California San Diego, La Jolla, California, USA
Rebecca Tsai
Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Brett Austin
San Diego County Public Health Lab, San Diego, California, USA
William Jordan
San Diego County Public Health Lab, San Diego, California, USA
Menka Asudani
San Diego County Public Health Lab, San Diego, California, USA
Amanda Walster
San Diego County Public Health Lab, San Diego, California, USA
Celestine G. Magallanes
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, La Jolla, California, USA
Holly Valentine
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, La Jolla, California, USA
Araz Manjoonian
Herbert Wertheim School of Public Health, University of California San Diego, La Jolla, California, USA
Carrissa Wijaya
Herbert Wertheim School of Public Health, University of California San Diego, La Jolla, California, USA
Vinton Omaleki
Herbert Wertheim School of Public Health, University of California San Diego, La Jolla, California, USA
Stefan Aigner
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Nathan A. Baer
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Maryann Betty
Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Anelizze Castro-Martínez
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Willi Cheung
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Peter De Hoff
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Emily Eisner
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Abbas Hakim
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Alma L. Lastrella
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Elijah S. Lawrence
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Toan T. Ngo
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Tyler Ostrander
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Ashley Plascencia
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Shashank Sathe
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Elizabeth W. Smoot
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Aaron F. Carlin
Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, USA
Gene W. Yeo
Expedited COVID Identification Environment (EXCITE) Laboratory, Department of Pediatrics, University of California San Diego, La Jolla, California, USA
Louise C. Laurent
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, La Jolla, California, USA
Anna Liza Manlutac
San Diego County Public Health Lab, San Diego, California, USA
Rebecca Fielding-Miller
Herbert Wertheim School of Public Health, University of California San Diego, La Jolla, California, USA
Rob Knight
Department of Bioengineering, University of California San Diego, La Jolla, California, USA
ABSTRACT A promising approach to help students safely return to in person learning is through the application of sentinel cards for accurate high resolution environmental monitoring of SARS-CoV-2 traces indoors. Because SARS-CoV-2 RNA can persist for up to a week on several indoor surface materials, there is a need for increased temporal resolution to determine whether consecutive surface positives arise from new infection events or continue to report past events. Cleaning sentinel cards after sampling would provide the needed resolution but might interfere with assay performance. We tested the effect of three cleaning solutions (BZK wipes, Wet Wipes, RNase Away) at three different viral loads: “high” (4 × 104 GE/mL), “medium” (1 × 104 GE/mL), and “low” (2.5 × 103 GE/mL). RNase Away, chosen as a positive control, was the most effective cleaning solution on all three viral loads. Wet Wipes were found to be more effective than BZK wipes in the medium viral load condition. The low viral load condition was easily reset with all three cleaning solutions. These findings will enable temporal SARS-CoV-2 monitoring in indoor environments where transmission risk of the virus is high and the need to avoid individual-level sampling for privacy or compliance reasons exists. IMPORTANCE Because SARS-CoV-2, the virus that causes COVID-19, persists on surfaces, testing swabs taken from surfaces is useful as a monitoring tool. This approach is especially valuable in school settings, where there are cost and privacy concerns that are eliminated by taking a single sample from a classroom. However, the virus persists for days to weeks on surface samples, so it is impossible to tell whether positive detection events on consecutive days are a persistent signal or new infectious cases and therefore whether the positive individuals have been successfully removed from the classroom. We compare several methods for cleaning “sentinel cards” to show that this approach can be used to identify new SARS-CoV-2 signals day to day. The results are important for determining how to monitor classrooms and other indoor environments for SARS-CoV-2 virus.
