The effectiveness of interventions to reduce COVID-19 transmission in a large urban jail

ABSTRACT Objectives To estimate the impact of various mitigation strategies on COVID-19 transmission in a U.S. jail beyond those offered in national guidelines. Methods We developed a stochastic dynamic transmission model of COVID-19 in one large urban U.S. jail among staff and incarcerated individuals. We divided the outbreak into four intervention phases: the start of the outbreak, depopulation of the jail, increased proportion of people in single cells, and asymptomatic testing. We used the next generation method to estimate the basic reproduction ratio, R 0 , in each phase. We estimated the fraction of new cases, hospitalizations, and deaths averted by these interventions along with the standard measures of sanitization, masking, and social distancing interventions. Results For the first outbreak phase, the estimated R 0 was 8.23 (95% CrI: 5.01-12.90), and for the subsequent phases, R 0, phase 2 = 3.58 (95% CrI: 2.46-5.08), R 0, phase 3 = 1.72 (95% CrI: 1.41-2.12), and R 0, phase 4 = 0.45 (95% CrI: 0.32-0.59). In total, the jail’s interventions prevented approximately 83% of projected cases and hospitalizations and 89% of deaths over 83 days. Conclusions Depopulation, single celling, and asymptomatic testing within jails can be effective strategies to mitigate COVID-19 transmission in addition to standard public health measures. Policy Implications Decision-makers should prioritize reductions in the jail population, single celling, and testing asymptomatic populations, as additional measures to manage COVID-19 within correctional settings.