We evaluated the impact of a test-to-stay (TTS) program on within-school transmission and missed school days in optionally masked kindergarten through 12th grade schools during a period of high community severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission.


Close contacts of those with confirmed SARS-CoV-2 infection were eligible for enrollment in the TTS program if exposure to a non-household contact occurred between 11/29/2021 and 01/28/2022. Consented participants avoided school exclusion if they remained asymptomatic and rapid antigen testing at pre-specified intervals remained negative. Primary outcomes included within-school tertiary attack rate (test positivity among close contacts of positive TTS participants) and school days saved among TTS participants. We estimated the number of additional school-acquired cases resulting from TTS and eliminating school exclusion.


A total of 1675 participants tested positive or received at least one negative test between days 5 and 7, and completed follow-up; 92% were students and 91% were exposed to an unmasked primary case. We identified 201 positive cases. We observed a tertiary attack rate of 10% (95% CI 6–19%) and 7,272 (89%) of potentially missed days were saved through TTS implementation. We estimated one additional school-acquired case for every 21 TTS participants remaining in school buildings during the entire study period.


Even in the setting of high community transmission, a TTS strategy resulted in substantial reduction in missed school days in optionally masked schools.

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Competing Interests

CONFLICT OF INTEREST DISCLOSURES: Dr. Benjamin reports consultancy for Allergan, Melinta Therapeutics, Sun Pharma Advanced Research Co. Drs. Boutzoukas and Moorthy receive salary support through the US government National Institute of Child Health and Human Development (NICHD) T32 training grant (1T32HD094671). Dr. Kalu reports funding from CDC Epicenter and receives consultancy fees from IPEC Experts and Wayfair. Dr. Brookhart serves on scientific advisory committees for AbbVie, Amgen, Atara Biotherapeutics, Brigham and Women’s Hospital, Gilead, and Vertex. Dr. Weber is a consultant and speaker for Pfizer on COVID-19 vaccines. The other authors have no financial relationships relevant to this article to disclose. Dr. Zimmerman reports funding from the National Institutes of Health (NIH) and US Food and Drug Administration (FDA)