By Eric Reinhart,  Daniel L. Chen

IMPORTANCE Mass incarceration is known to foster infectious disease outbreaks, amplification of infectious diseases in surrounding communities, and exacerbation of health disparities in disproportionately policed communities. To date, however, policy interventions intended to achieve epidemic mitigation in US communities have neglected to account for decarceration as a possible means of protecting public health and safety. OBJECTIVE To evaluate the association of jail decarceration and government anti-contagion policies with reductions in the spread of SARS-CoV-2. DESIGN, SETTING, AND PARTICIPANTS This cohort study used county-level data from January to November 2020 to analyze COVID-19 cases, jail populations, and anti contagion policies in a panel regression model to estimate the association of jail decarceration and anti-contagion policies with COVID-19 growth rates. A total of 1605 counties with data available on both jail population and COVID-19 cases were included in the analysis. This sample represents approximately 51% of US counties, 72% of the US population, and 60% of the US jail population. EXPOSURES Changes to jail populations and implementation of 10 anti-contagion policies: nursing home visitation bans, school closures, mask mandates, prison visitation bans, stay-at-home orders, and closure of nonessential businesses, gyms, bars, movie theaters, and restaurants. MAIN OUTCOMES AND MEASURES Daily COVID-19 case growth rates. RESULTS In the 1605 counties included in this study, the mean (SD) jail population was 283.38 (657.78) individuals, and the mean (SD) population was 315.24 (2151.01) persons per square mile. An estimated 80% reduction in US jail populations, achievable through noncarceral management of nonviolent alleged offenses and in line with average international incarceration rates, would have been associated with a 2.0% (95% CI, 0.8%-3.1%) reduction in daily COVID-19 case growth rates. Jail decarceration was associated with 8 times larger reductions in COVID-19 growth rates in counties with above-median population density (4.6%; 95% CI, 2.2%- 7.1%) relative to those below this median (0.5%; 95% CI, 0.1%-0.9%). Nursing home visitation bans were associated with a 7.3% (95% CI, 5.8%-8.9%) reduction in COVID-19 case growth rates, followed by school closures (4.3%; 95% CI, 2.0%-6.6%), mask mandates (2.5%; 95% CI, 1.7%-3.3%), prison visitation bans (1.2%; 95% CI, 0.2%-2.2%), and stay-at-home orders (0.8%; 95% CI, 0.1%-1.6%). CONCLUSIONS AND RELEVANCE Although many studies have documented that high incarceration rates are associated with community-wide health harms, this study is, to date, the first to show that decarceration is associated with population-level public health benefits. Its findings suggest that, among other anti-contagion interventions, large-scale decarceration and changes to pretrial detention policies  are likely to be important for improving US public health, biosecurity, and pandemic preparedness. 

AMA Network Open. 2021;4(9):e2123405