Abstract
INTRODUCTION: Real-world evidence on the utility of SARS-CoV-2 mass screening in correctional facilities remains limited. The Connecticut Department of Correction (CTDOC) implemented an adaptive testing programme involving serial mass screening with reverse transcription PCR (RT-PCR). Data from this programme offer a unique opportunity to evaluate mass screening throughout the pandemic. METHODS: We conducted a longitudinal analysis of people tested as part of mass screening between November 2020 and May 2023 while housed in a CTDOC cell. We estimated the time to test result and the average number of exposures averted by isolating residents who tested positive. Averted exposures were calculated by comparing exposures in the 14 days following a positive versus negative test. RESULTS: Among the 600 477 recorded tests, collected among 29 728 residents, 177 845 were collected during mass screening and included. Median time from test collection to result notification was 2 days (IQR: 1-3) for positives and 1 day (IQR: 1-2) for negatives. Among residents who tested positive during mass screening, the average number of susceptible cellmates declined from 1.23 on the test day to 0.16 by day 8; at the cell block level, susceptible contacts fell from 79.5 to 0.19 by day 9. These declines corresponded with an average of 0.65 (95% CI: 0.62 to 0.67) cell and up to 66.9 (95% CI: 64.7 to 69.1) cell block exposures adverted per day per positive case. However, between testing and result notification, residents who tested positive had an average of 1.19 (95% CI: 1.15 to 1.23) susceptible cellmates and 73.0 (95% CI: 71.4 to 74.6) susceptible cell block contacts. CONCLUSIONS: Mass screening in correctional facilities can reduce exposures to respiratory pathogens, such as SARS-CoV-2, through timely identification and isolation. However, test delays, limited isolation capacity and missed infections allow ongoing transmission even in well-resourced settings, suggesting that testing alone is unlikely to fully mitigate transmission in correctional facilities.