UC San Diego

Background: People who inject drugs (PWID) are at an increased risk of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) from sharing of blood contaminated injection equipment and are defined by the World Health Organization as a key population for focus of prevention efforts for the UNAIDS HIV and WHO HCV 2030 targets.1-3 Despite evidence that harm reduction program such as needle and syringe programs (NSPs) and supervised consumption sites (SCS) reduce injecting risk, coverage of NSPs is low globally and SCS are only available in a few countries.4-6 To support expansion of these harm reduction interventions, research is needed to fill data gaps that remain in regards to the cost of implementation in many countries, how the COVID-19 pandemic impacted utilization of harm reduction services, and potential impact of the establishment of SCS on HIV and HCV among PWID..Methods: In Aim 1, we performed a global systematic review on the unit cost of NSP provision and used statistical modeling with the extracted cost estimates to predict the united cost per syringe distributed for 137 countries. In Aim 2, we used a longitudinal cohort of PWID in San Diego, California (La Frontera) to examine the changes during the COVID-19 pandemic of the risk environment, including access to harm reduction services and injecting risk. In Aim 3, we developed a dynamic HIV and HCV transmission model, to simulate the potential 10-year impact of establishment and scale-up of SCS to 20% coverage among PWID on future HIV and HCV incidence within three counties in California: San Francisco, Los Angeles, and San Diego. Results: In Aim 1, 55 estimates of the unit cost per syringe were collected from the literature from 14 countries and the unit costs were extrapolated for 137 countries, ranging from $0.08 to $20.77 (2020 USD) per syringe distributed. From Aim 2, from the 336 PWID enrolled in the La Frontera cohort who resided in San Diego at baseline and had at least one study follow-up visit, baseline harm reduction access was low (6% accessed NSP services, 10% received OAT), and over 12-months post-baseline we observed a decrease in receptive syringe sharing, an increase in recent NSP access, no change in OAT access, and a decrease in injecting heroin. In Aim 3, we scale-up of SCS coverage to 20% among PWID in three counties (San Francisco, Los Angeles, and San Diego) in California resulted in a decrease of new HIV infections (22%, 15%, and 14%, respectively) and new HCV infections (28%, 32%, and 27%, respectively) among PWID over 10 years. Conclusion: Harm reduction services are an important component of preventing the spread of HIV and HCV among PWID. By understanding the costs associated with implementation of NSPs, how the COVID-19 pandemic impacted utilization of harm reduction services, and the impact of SCS on HIV and HCV transmission, policies and funding can be established to help reach the UNAIDS HIV and the WHO HCV 2030 goals.