Impact of Pandemic-Induced Service Interruptions and Changes in Injecting Behaviors on HIV and Hcv Outbreaks within People Who Inject Drugs: A Modeling Study

Abstract

People who inject drugs (PWID) disproportionally carry high burden of HIV and HCV. During COVID-19 pandemic, routine access to harm reduction services (syringe services programs (SSP), medication for opioid use disorder (MOUD), etc.) and HIV/HCV treatment were disrupted due to redirection of resources to pandemic response and social distancing which also impact injecting behaviors and partnerships. These factors are closely related to the likelihood of engaging in high-risk injection practices. It is unknown, when the effects of service disruption and behavioral changes are combined, how COVID-19 pandemic changed the trajectory of HIV/HCV prevalence within the PWID population. 

This study is nested within the ALIVE (AIDS Linked to the IntraVenous Experience) Study, an ongoing community-based observational cohort of PWID in Baltimore, USA since 1988. We analyzed empirical data on injecting behaviors including injecting frequency and partnerships that were integrated into an individual-based model of HIV and HCV transmission amongst PWID. We simulated changes in injecting frequency, contacts, and cessation patterns in the context of a range of service interruptions (duration, magnitude, etc.). Our results show that median number of drug use network members dropped from 3 in 2019 to 1 in 2022, and probability of injecting with their network members halved (from 81.5% to 40.7%) while injection frequency slightly increased among active injectors. We also simulated a range of service interruptions from up to 3 months of full closure and up to 12 months of reduced capacity. In general, interruptions to SSP resulted in the highest increase in both HIV and HCV cases and HCV prevalence was more sensitive to any service interruptions. However, there was consistently lower HIV and HCV prevalence scaling with the duration of the behavioral changes described above (the addition of 1/3/5/ years of behavioral changes decreased total number of HCV cases by 6%/8%/13% and total HIV cases by 2.5%/3.3%/5.5%). No significant change in incidence of co-infection was observed. 

Model results combined with rich individual behavioral data from ALIVE indicate that pandemic-induced behavioral changes of PWID last much longer than service disruptions and can offset the increased disease burdens caused by interrupted service access.

Note: This conference abstract was presented at the 9th International Conference on Infectious Disease Dynamics organized by the journal Epidemics. This abstract has not been screened by SSRN for potential for public harm and should not be used to inform any clinical decision making. No competing interests or funding statements have been declared.