Many US communities vulnerable to HIV outbreak due to unsafe injecting of prescription opioids

Research published in the online edition of the Journal of Acquired Immune Deficiency Syndromes has identified the jurisdictions in the United States especially vulnerable to the rapid spread of HIV or hepatitis C virus (HCV) due to unsafe injecting drug use. A total of 220 countries in 26 states had a high level of vulnerability, with factors associated with unsafe injecting including high rates of death due to drug overdose, unemployment and poverty.

“We have developed a model to identify US counties potentially vulnerable to rapid spread of HIV, if introduced, and new or continuing high numbers of HCV infections among PWID [people who inject drugs],” comment the authors. “Jurisdictions identified as at-risk might use potentially informative local data that were not available nationally and take action.”

There has been a massive increase in opioid use in the United States over the past decade. This has fuelled an increase in unsafe drug injecting, leading to new HCV infections, especially in non-urban communities.

In late 2014, injection of prescription opioids was implicated in an outbreak of HIV in a rural US community (Austin in Scott County, Indiana). Almost all (92%) of those infected with HIV during this outbreak were also infected with HCV. Health officials were concerned about the potential for similar outbreaks in other communities. They therefore designed a model to identify the jurisdictions potentially vulnerable to the rapid spread of HIV, if the infections were introduced into groups illicitly injecting drugs.

Acute HCV infections were used as a proxy for illicit unsafe injecting.

Data on the number of acute HCV infections reported in 2012 (n = 1710) and 2013 (n = 2074) were included in investigators’ analyses. The county-level factors possibly associated with use of unsterilised injecting equipment were identified. For each vulnerable jurisdiction, the authors assessed the likelihood that HIV might be introduced into a network of people who inject drugs. This calculation took into account local HIV prevalence.

A total of 2970 counties reported acute HCV infections in the study period.

Six indicators were associated with the rate of new HCV infections:

• Drug overdose deaths per 100,000 population (p < 0.0001)

• Prescription opioid sales per 10,000 population (p = 0.012)

• Higher percentage of white, non-Hispanic population (p < 0.0001)

• Lower per-capita income (p < 0.0001)

• Higher rate of adult unemployment (p = 0.0095)

• Buprenorphine prescription for opioid substitution treatment per 10,000 population.

The authors identified 220 counties in 26 states that were especially vulnerable to an HIV outbreak spread by injecting drug use.

“The counties identified in our analysis were overwhelmingly rural,” note the authors. “Since 2006, rates of acute HCV infection have increased faster in rural than in urban areas consistent with introduction and spread of this infection into populations made newly vulnerable by the expansion of IDU in rural America.”

Unemployment and poverty were important risk factors for acute HCV infection. “It has been hypothesized that financial stressors increase vulnerability to drug use so that young adults in economically deprived areas may accumulate risk factors for drug use and be likely to establish drug dependencies at a younger age than persons in more economically privileged areas,” write the researchers.

Local HIV prevalence rates ranged between 0.9 to 38 per 10,000 population, and with one exception, the vulnerable counties had a prevalence rate below the national prevalence of 29 per 10,000 population.

“All health officials can review these results along with the most recent sources of data on HIV and acute HCV diagnoses available to them. Additional local insights may be gained by examining data sources associated with IDU that were not available for inclusion in our analysis,” conclude the authors. “To reduce vulnerability, targeted interventions in accordance with efforts to prevent and treat substance use disorder and to reduce risk of infectious complications of IDU are warranted.”