Managing HIV and Hepatitis C Outbreaks Among People Who Inject Drugs: A Guide for State and Local Health Departments

The United States is in the midst of an opioid misuse epidemic involving prescription drugs, as well as heroin and other synthetic opioids (e.g., fentanyl). This crisis has led to increases in drug overdose deaths, admissions for substance use treatment, and neonatal abstinence syndrome. Deaths caused by drug overdoses increased from 6.2 per 100,000 in 2000 to 14.7 per 100,000 in 2014, and admissions to substance-use treatment facilities increased from <1 per 10,000 in 1999 to approximately 4 per 10,000 in 2009. In addition, the incidence of neonatal abstinence syndrome increased from 1.5 per 1,000 births in 1999 to 6.0 per 1,000 births in 2013. In 2014, an estimated 1.9 million persons had substance use disorders involving prescription pain relievers, and 586,000 persons had substance use disorders involving heroin. Precise data on the number of people who inject drugs (PWID) in the United States is lacking; however, estimates for the numbers of PWID in 2011 ranged from 500,000 to 1 million persons. 

The opioid epidemic has also increased the number of PWID in the United States and thereby substantially increased the risk of transmission of bloodborne viruses, including human immunodeficiency virus (HIV), hepatitis C virus (HCV) and hepatitis B virus (HBV) through use of shared equipment. Unsafe injection of drugs, such as by sharing injection equipment (e.g., syringes, cookers, water, and cotton) to inject or split drugs, contributed to an increase in new HCV infections from 1,232 to 2,436 from 2011 through 2015. Although PWID make up 1%–3% of the total population, injection drug use accounted for approximately 6% of new HIV diagnoses in 2015; infections attributable to the combined risk of male-to-male sexual contact and injection drug use accounted for another 3% of diagnoses. Among persons diagnosed with acute HCV infection and information about injection drug use in 2015, 64% were PWID.

Rural communities are disproportionately affected by the opioid epidemic and have been most affected by overdoses, new acute HCV infections, and are considered most vulnerable to rapid spread of HIV and HCV if introduced among uninfected communities of PWID. Identifying jurisdictions particularly vulnerable to an HIV or HCV outbreak can guide public health efforts to detect, prevent, and respond quickly to, potential outbreaks. Although numbers and rates of acute hepatitis C infections are proportionally greater in rural communities, significant increases have also been recorded in urban counties.

The potential for rapid spread of HIV among this new population of PWID was realized during a 2015 outbreak in rural Scott County, Indiana. In January 2015, disease intervention specialists (DIS) reported 11 new cases of confirmed HIV infection epidemiologically linked through injection drug use; by comparison, only 5 HIV infections had been diagnosed in this county in the prior 10 years (2004–2013). By November 2015, 181 new cases of HIV had been diagnosed; 92% of infected persons were coinfected with HCV. The impact of injection drug use can be far reaching, and PWID have a wide range of needs that may complicate their ability to follow the treatment and prevention recommendations essential to controlling an outbreak. Lack of medical care capacity for HIV and HCV infection as well as limited local resources for prevention and treatment of substance use disorder may have allowed this outbreak to spread faster and further than it would have had these resources been present. Controlling the outbreak involved establishing these services, especially provision of antiretroviral therapy for HIV infection. Additional activities that further aided control included use of advanced HIV and HCV molecular technologies to characterize the network of PWID, rapid deployment of DIS teams to conduct contact tracing and HIV and HCV testing throughout the affected community, and use of the state’s emergency preparedness resources to coordinate a multitude of other services (e.g., insurance enrollment, care coordination, vaccinations). Advanced planning can facilitate an effective coordinated response for communities faced with the possibility of similar future outbreaks of HIV or HCV among networks of PWID. This document is intended to help health departments prepare for such an outbreak. The document provides guidance on how to plan for an outbreak of HIV or HCV among PWID including considerations for developing an outbreak response plan to minimize the impact of the outbreak on the community and stop further transmission. The document also outlines strategies to detect and investigate a possible outbreak.