A Study of SARS-COV-2 Outbreaks in US Federal Prisons: the Linkage Between Staff, Inmate, and Community Transmission

Background Since the novel coronavirus SARS-COV-2 was first identified to be circulating in the US on January 20, 2020, some of the worst outbreaks have occurred within state and federal prisons. The vulnerability of inmate populations, and the additional threats posed to the health of prison staff and the people they contact in surrounding communities underline the need to better understand the dynamics of transmission in the inter-linked inmate/staff/community sub-populations to better inform optimal control of SARS-COV-2. Methods We examined SARS-CoV-2 case data from 101 non-administrative federal prisons between 5/18/2020 to 01/31/2021 and examined the per capita size of outbreaks in staff and inmates compared to outbreaks in the communities in the counties surrounding the prisons during the summer and winter waves of the SARS-COV-2 pandemic. We also examined the impact of decarceration, comparing inmate, staff and community SARS-COV-2 outbreak sizes during the winter wave to the summer wave. Results For both the summer and winter waves we found significant inter-correlations between per capita rates in the outbreaks among inmates, staff, and the community.Over-all during the pandemic, per capita rates were significantly higher in inmates than in both the staff and community (paired Student’s t-test p=0.03 and p<0.001, respectively). Per capita rates of inmate outbreaks depended significantly on security level, ranked from lowest to highest: High, Minimum, Medium, and Low security (population standardized Negative Binomial factor regression p=0.02).Federal prisons decreased the number of inmates by a relative factor of 96% comparing the winter to summer wave (one SD range [90%,102%]). Prisons with relative decarceration below the mean had significantly lower ratio of winter to summer per capita rates in inmates, and also in the surrounding counties (two-sided Student’s t-test p=0.04 and p=0.02, respectively). To our knowledge, this is the first analysis to examine the impact of decarceration on community rates of SARS-COV-2 transmission. Conclusions We found significant evidence of community/staff/inmate inter-linkage of SARS-COV-2 transmission. Decarceration ameliorates both prison and community SARS-COV-2 per capita rates. Further study is warranted to determine which control measures aimed at inmates and/or staff are most efficacious at preventing or controlling outbreaks.