SAFER-C™ Simulation Provides Vital COVID Data in Washington, D.C. Correctional Facilities
CNA's Center for Justice Research and Innovation is helping Washington D.C Department of Corrections (DOC) leaders make decisions about COVID safety measures in its facilities. The department has used the insights from a new report, SAFER-C™ Getting Back to Normal, to inform its reopening protocols and responses to emerging concerns with infections from new strains.
“During this ongoing pandemic, U.S. jails face challenges providing safety, security, programming, and care while limiting virus transmission,” said Chip Coldren, director of CNA’s Center for Justice Research and Innovation. “We customized an agent-based model, SAFER-C™, to simulate the operations, environment and virus spread within a representative jail facility in a way that supports critical programmatic and operational decision-making.”
As part of this research, CNA set out to answer questions about the effects of different vaccination rates among the resident population and the impact of reintroducing high-contact activities like basketball. The simulation results provide insight to support decisions by jail leadership as they transition to higher activity levels and resume out-of-cell activities while mitigating and managing COVID-19 transmission risks. The model revealed several important findings:
- Infections were more commonly transmitted from staff to staff and resident to resident than from staff to resident or resident to staff.
- The highest-risk activities involved community-to-staff interactions, daily staff-to-staff interactions, resident out-of-cell time, pat-downs and searches, and movement of residents outside the housing unit.
- The average risk of infections was observed to vary only slightly with as the number of residents allowed out-of-cell simultaneously grew from 10 to 20 to 40. But the risk of a severe outbreak was observed to increase with larger group sizes.
- Infections can be higher in groups of vaccinated and unvaccinated persons engaging in activities together without social distancing, such as using phone banks. Vaccinated individuals who are infected are often asymptomatic, thus behaving like additional seeds, and may continue to transmit infection undetected until the first symptomatic case is observed.
- The case resulted in an average of 3.6 resident cases and 16.3 staff cases over 25 days. More than 80% of those staff cases were from community spread—infected outside of the jail. In addition, 98% of all iterations reported no resident fatalities, while 79% reported no staff fatalities.
- The average number of infected residents varied widely under eight different COVID protocols tested, from 2.4 to 23.9 infections.
- Resumption of high-contact activities like basketball resulted in the highest average number of infections among the scenarios, especially when multiple infectious resident seeds were introduced. High vaccination rates were shown to lower the number of infections slightly.
- If intakes were not quarantined, the average number of resident cases increased to 31 from 20 over the 25-day period.
“The findings about the predominance of staff-to-staff and resident-to-resident transmission resulted in reinforced messaging to maintain social distancing when interacting with peers,” said Dr. Reena Chakraborty, DC DOC chief of strategic planning and analysis. “SAFER-C results also informed reopening decisions about group sizes and the resumption of basketball, especially in mixed groups or among unvaccinated residents. Simulations also helped explain a plateau in observed overall effective resident vaccination rates, despite increased resident participation in vaccination efforts. Based on these insights, we believe SAFER-C is a valuable tool that can help advance the use of data-driven insights by correctional leaders.”
The SAFER-C model uses data specific to an individual facility to estimate infections and deaths. Decision-makers can use it to predict the impacts of a wide range of decisions, including starting or stopping inmate work programs, serving meals in cells or in mess halls, changing the length of isolation for infected individuals, and opening or closing gym and workout facilities.