Impact of routine opt-out HIV/HCV screening on testing uptake at a syringe services program: An interrupted time series analysis.

Background: Hepatitis C (HCV) is the most common infectious disease among people who inject drugs (PWID). Engaging PWID in harm reduction services, such as syringe service programs (SSPs), is critical to reduce HCV and HIV transmission. Additionally, testing for HIV and HCV among PWID is important to improve diagnosis and linkage to care. On March 1, 2018, Florida's only legal SSP implemented bundled opt-out HIV/HCV testing at enrollment. We aimed to examine the differences in HIV/HCV testing uptake before and after the implementation of the opt-out testing policy.

Methods: Multivariable logistic regression was used to assess predictors of accepting HIV/HCV tests, controlling for opt-in and opt-out policy. Monthly estimates of the percent of participants accepting an HIV test, HCV test, or both were generated. Interrupted Time Series (ITS) analysis evaluated the immediate policy impact on level of uptake and trend in uptake over time for bundled HIV/HCV testing before and after the opt-out testing policy.

Results: The total study period was 37 months between December 2016-January 2020 with 512 SSP participants 15 months prior and 547 SSP participants 22 months after implementation of bundled HIV/HCV opt-out testing. Significant predictors of accepting both HIV/HCV tests were cocaine injection (aOR = 2.36), self-reported HIV positive status (aOR = 0.39) and self-reported HCV positive status (aOR = 0.27). Based on the ITS results, there was a significant increase in uptake of HIV/HCV testing by 42.4% (95% CI: 26.2%-58.5%, p < 0.001) immediately after the policy change to opt-out testing.

Conclusion: Bundled opt-out HIV/HCV testing substantially increased the percentage of SSP clients who received HIV and HCV rapid tests at enrollment into the program, and the effect remained stable across the 22 months post opt-out testing policy. Future investigation must assess PWID-level perspective of testing preferences and examine whether this testing approach improves HIV/HCV detection among PWID previously unaware of their status.