Case Investigation and Contact Tracing in US State and Local Public Health Agencies: Sustaining Capacities and Applying Lessons Learned From the COVID-19 Pandemic and 2022 Mpox Outbreak.

The COVID-19 pandemic illuminated the lack of resources available to US state and local public health agencies to respond to large-scale health events. Two response activities that were notably underresourced are case investigation and contact tracing (CI/CT), which health agencies routinely employ to control and prevent the transmission of infectious diseases. However, the scale of contact tracing required during the COVID-19 pandemic exceeded available resources, even in high-capacity public health agencies. For both routine outbreak response and epidemic preparedness, health agencies must have CI/CT program capacities in place prior to the detection of an outbreak to be ready to respond. Our research builds on previous work to identify the baseline CI/CT capacities needed in US state and local public health agencies to respond to any type of outbreak. Fifteen public health officials representing 10 public health agencies and 4 experts in CI/CT were interviewed about various aspects of their CI/CT program during the COVID-19 pandemic. The interviews coincided with the beginning of the 2022 mpox epidemic. Discussions on CI/CT during that response were collected to augment the interviews, where possible. Findings revealed that CI/CT capacities were underresourced prior to and during the pandemic, as well as during the mpox outbreak, even after substantial additional resourcing and efforts to scale up. Moreover, state and local health agencies encountered challenges in pivoting their COVID-19 CI/CT capacities for the mpox response, suggesting that CI/CT programs should either be designed with flexibility in mind, or should allow for specialization based on the pathogen's mode of transmission and the population at risk. Federal, state, and local health agency staff and officials should consider lessons learned from this research to plan for readily scalable and sustainable CI/CT programs to ensure readiness for future outbreaks.