A holistic evaluation of sexual health disease investigation: case study of the 2022 Mpox outbreak in Santa Clara County, California

Background Despite its integral role in preventing and controlling infectious diseases, there is limited research that evaluates the impact of disease investigation (DI) services. The County of Santa Clara Public Health Department activated its emergency response operations, which included designated DI services, to respond to its local Mpox outbreak. The aim of this evaluation was to understand the range of outcomes achieved through Mpox DI services. Methods Mpox investigations completed between June and December 2022 were included in an evaluation that employed a composite measure to calculate the number of investigations needed to achieve the following outcomes: (1) treatment completion, (2) monitoring completion, (3) partial vaccine dose completion, (4) full vaccination series completion, and (5) STI and HIV testing. Results The overall composite score of 0.53 indicated that each investigation led to 1.90 outcomes achieved. Among cases eligible for treatment, 2.16 investigations yielded one treatment completion; 1.19 case and contact investigations yielded one monitoring completion; 2.21 and 3.53 contact investigations yielded one partial vaccine dose completion and one full vaccination series completion, respectively; and 2.25 case and contact investigations yielded one STI or HIV test. Conclusion Recognizing the multiple steps involved in DI can inform holistic evaluations that illuminate intervention impact.