Epidemiology of COVID-19 Among Incarcerated Individuals and Staff in Massachusetts Jails and Prisons

Incarcerated populations have exceptionally high risk of coronavirus disease 2019 (COVID-19) transmission and mortality due to overcrowding, movement through facilities, and high rates of chronic illness; hence, physical distancing is not a viable mitigation strategy.1 As of June 6, 2020, at least 42 107 cases and 510 deaths have occurred among individuals incarcerated in US prisons.2 Decarceration and increased testing may reduce transmission, but their efficacy is uncertain.3 Jails confine nearly one-third of incarcerated individuals, but data on COVID-19 in jails are limited. However, Massachusetts reports data on COVID-19 in both county jails and state prisons. We describe the COVID-19 burden in these settings and its association with decarceration and testing rates.


Introduction
Incarcerated populations have exceptionally high risk of coronavirus disease 2019  transmission and mortality due to overcrowding, movement through facilities, and high rates of chronic illness; hence, physical distancing is not a viable mitigation strategy. 1 As of June 6, 2020, at least 42 107 cases and 510 deaths have occurred among individuals incarcerated in US prisons. 2 Decarceration and increased testing may reduce transmission, but their efficacy is uncertain. 3 Jails confine nearly one-third of incarcerated individuals, but data on COVID-19 in jails are limited.
However, Massachusetts reports data on COVID-19 in both county jails and state prisons. We describe the COVID-19 burden in these settings and its association with decarceration and testing rates.

Methods
Data used in this cohort study were reported by 16 Massachusetts Department of Corrections (MA DOC) facilities and 13 county-level systems from April 5 through July 8, 2020, pursuant to a court order. 4 This study used publicly available, deidentified data and was deemed exempt from institutional review board approval by Partners HealthCare. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.
We used baseline facility populations to calculate cumulative testing and laboratory-confirmed case rates per 1000 persons and changes in incarcerated population size (ie, decarceration). Case and testing rates among staff could not be calculated. We report rate ratios (RR) for individuals incarcerated in Massachusetts relative to the state and US general populations. 5,6 Analyses were conducted in R, version 3.6.3 (R Foundation).
Overall, systems with higher testing rates had higher case rates (Figure, A). For example, the testing rate across all county jails was 254 per 1000 persons, with a case rate of 36 cases per 1000 persons, whereas MA DOC facilities had a testing rate of 1093 per 1000 persons and a case rate of 52 cases per 1000 persons. The proportion of positive tests among incarcerated individuals in county facilities was higher (14%) than in MA DOC facilities (5%) and the general Massachusetts (9%) and US (8%) populations. Case incidence was higher among systems that released a lower proportion of their baseline population (Figure, B). The MA DOC case rate was 52 cases per 1000 persons with a population decrease of 9% compared with all county jails, which had a case rate of 36 case per 1000 persons and decreased their overall population by 21%. County jails released up to 35% of incarcerated individuals. A gradual decline in reported cases among incarcerated individuals and staff was observed, corresponding to a decrease of 15% in the incarcerated population.

Discussion
To our knowledge, this is the first examination of COVID-19 burden among incarcerated individuals and staff in both jails and prisons. The rate of COVID-19 among incarcerated individuals was nearly 3 times that of the Massachusetts general population and 5 times the US rate, consistent with recent reports in US federal and state prisons. 2 Systems with smaller reductions in incarcerated populations and higher testing rates demonstrated higher rates of confirmed cases. Limited testing likely underestimates the true infection rate in county jails, where nearly one-third of tests were positive. These data are limited by absence of deaths and demographic characteristics. Owing to structural racism and the criminalization of poverty, COVID-19 racial/ethnic inequities may be exacerbated among incarcerated individuals. Whereas rates of COVID-19 vary nationwide, our results add to a growing body of literature emphasizing high COVID-19 rates in carceral settings and the importance of testing and decarceration. [1][2][3] Rates of COVID-19 in Massachusetts jails and prisons are alarmingly high and require urgent action. Reporting of COVID-19 data from carceral facilities is highly variable and generally excludes county jails; hence, standardization is needed. Access to testing without coercion, decarceration, and contact tracing are necessary to decrease harm from COVID-19 to incarcerated people and their communities.