Association of COVID-19 Quarantine Duration and Postquarantine Transmission Risk in 4 University Cohorts

Abstract

IMPORTANCEOptimal quarantine length for COVID-19 infection is unclear, in part owing to limited empirical data. OBJECTIVE To assess postquarantine transmission risk for various quarantine lengths and potential associations between quarantine strictness and transmission risk. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study in 4 US universities from September 2020 to February 2021, including 3641 university students and staff who were identified as close contacts to individuals who tested positive for SARS-CoV-2 infection. Individuals were tested throughout the 10 to 14-day quarantine, and follow-up testing continued at least weekly throughout the 2020-2021 academic year. EXPOSURES Strict quarantine, including designated housing with a private room, private bathroom, and meal delivery, vs nonstrict, which potentially included interactions with household members. MAIN OUTCOMES AND MEASURES Dates of last known exposure, last negative test result, and first positive test result during quarantine. RESULTSThis study included 301 quarantined university students and staff who tested SARS-CoV-2-positive (of 3641 quarantined total). These 301 individuals had a median (IQR) age of 22.0 (20.0-25.0) years; 131 (43.5%) identified as female; and 20 (6.6%) were staff. Of the 287 selfreporting race and ethnicity according to university-defined classifications, 21 (7.3%) were African American or Black, 60 (20.9%) Asian, 17 (5.9%) Hispanic or Latinx, 174 (60.6%) White, and 15 (5.2%) other (including multiracial and/or multiethnic). Of the 301 participants, 40 (13.3%; 95% CI, 9.9%-17.6%) had negative test results and were asymptomatic on day 7 compared with 15 (4.9%; 95% CI, 3.0%-8.1%) and 4 (1.4%; 95% CI, 0.4%-3.5%) on days 10 and 14, respectively. Individuals in strict quarantine tested positive less frequently than those in nonstrict quarantine (10% vs 12%; P = .04). CONCLUSIONS AND RELEVANCETo maintain the 5% transmission risk used as the basis for US Centers for Disease Control and Prevention's 7-day test-based quarantine guidance, our data suggest that quarantine with quantitative polymerase chain reaction testing 1 day before intended release should be 10 days for nonstrict quarantine and 8 days for strict quarantine, as ongoing exposure during quarantine may be associated with the higher rate of positive test results following nonstrict quarantine.

Buildout and integration of an automated high-throughput CLIA laboratory for SARS-CoV-2 testing on a large urban campus

“…A study on matched anterior nares swabs tested with both RT-PCR and Abbott BinaxNOW TM (Abbott Laboratories, Chicago, IL) was critical during the omicron surge as the demand for rapid diagnostic tests increased [28] . Data from the BU CTL, contact tracing, and sequencing data provided insight on vaccine efficacy [30] , transmission of SARS-CoV-2 in classrooms [31] , post-quarantine transmission and quarantine length [32] , and isolation release after infection [33] .…”

Comparison of different isolation periods for preventing the spread of COVID-19: a rapid systematic review and a modelling study

“…19 We used Freeman-Tukey double arcsine transformation to stabilize variances. 20 We assessed the between-study heterogeneity with a visual inspection of forest plots and the I 2 statistic.…”

“…Isolating infected patients and quarantining individuals with a high risk of recent infection remain widely used strategies to prevent the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). 2,3 The current World Health Organization (WHO) recommendations, published on June 17 2020 4 and September 15 2022 5 , for discharging patients from isolation differ for symptomatic and asymptomatic patients. For symptomatic patients, WHO recommends ten days after symptom onset plus at least three additional days without symptoms.…”

Evaluating the COVID-19 Containment Protocol in Greek Universities for the Academic Year 2021–2022

“…In the first category, efforts were made to assess the control plans used for reopening universities (e.g., Boston University in [ 4 ], Harvard/Boston/Duke/Northeastern in [ 5 ], Bristol (UK) in [ 6 ], Southern California in [ 7 ], Purdue in [ 8 ], Tulane in [ 9 ], Clemson in [ 10 ]); or to develop relevant susceptible–exposed–infected–recovered (SEIR) or agent-based (ABM) models in a university environment (e.g., Emory University in [ 11 ], University of Illinois in [ 12 ]). In the second category, research was focused on studying how COVID-19 containment protocols decreased transmission among university students (e.g., Saint Louis University in [ 13 ], Boston University in [ 14 ]) and to assess how the Omicron variant was established in universities (e.g., Harvard/Boston/Northeastern in [ 15 ], University of Washington in [ 16 ]).…”