Once outbreak was recognized, program put in place reduced number of ongoing transmissions, modeling shows
In 2015, when 181 of rural Scott County, Indiana's 24,000 residents were diagnosed with HIV, the data signaled the largest HIV outbreak in a rural setting among people who were injecting drugs yet seen in the United States.
Triggering the declaration of a public health emergency, the outbreak also led to the opening of the first legal sterile syringe program in Indiana. By then, it is estimated, according to authors of a recent Clinical Infectious Diseases report, about 80% of all of the HIV infections resulting from the outbreak that would eventually be diagnosed had already occurred.
A sterile syringe program already in place as a public health intervention in a community where the prevalence of injecting drug use was estimated at 1.7% would have averted 178 HIV infections stemming from the outbreak, a modeling study conducted by the authors found, 154 HIV infections among people who were injecting drugs and 24 HIV infections averted among partners not injecting drugs. The program that was put in place made a difference as well, the authors found, averting 119 infections overall.
While strong surveillance efforts and early case-finding, approaches included in the administration's 10-year plan to end HIV as an epidemic in the U.S., can significantly reduce the spread of new, cluster-driven outbreaks, they require a means to reach people who are often vulnerable, marginalized and facing significant barriers to services, the authors note. Worldwide, they write, an estimated three million people who inject drugs and live with HIV face those barriers.
Serving not only to break chains of infectious disease transmissions occurring because of shared injecting equipment, the authors note, sterile syringe programs serve as entry points to health, substance use disorder and social services, enabling earlier diagnosis, treatment, and suppression of viruses to untransmissable levels.
In what they write appears to be the first study to model and compare the benefits of sterile syringe programs -- both in place before an infectious disease outbreak occurs, and put in place once an outbreak has been recognized, the authors calculated the impacts of factors that included diagnosis on needle-sharing and sexual practices, of treatment on viral suppression, as well as of the spread of infections through shared equipment. They note that focusing on HIV transmission alone, their study likely underestimates the public health benefit of sterile syringe programs.
