A modeling analysis suggests state officials in Indiana could have prevented upwards of 95% of the HIV cases in a 2014 outbreak.
Gregg S. Gonsalves, PhD
An outbreak of HIV infections in a rural Indiana county could have been much smaller if public health officials had implemented a more robust surveillance program, according to a new modeling study.
Scott County, a half-hour drive north of Louisville, KY, has only about 24,000 residents. And yet, the county became the epicenter of a major HIV outbreak, beginning when the first patient was diagnosed in November of 2014. Within 2 months, 17 cases had been reported and the state’s Department of Health had been called in to investigate. By August of 2015, over 180 new infections were attributed to the HIV outbreak. By 2017, the number had reached 215.
Officials quickly zeroed in on a cause: the opioid epidemic. As more people began injecting drugs, the number of new HIV infections continued to climb.
In a new study analyzing the state’s response and modeling the impacts of alternative actions, researchers from Yale University noted that Indiana state law banned new opioid agonist therapies. Syringe exchange programs were also not available. Had the state detected the outbreak in January 2013 and adopted a robust containment strategy, the vast majority of new infections could have been avoided, concluded authors Gregg S. Gonsalves, PhD, and Forrest W. Crawford, PhD, both of Yale University.
Forrest W. Crawford, PhD
“Initiation of a response on Jan 1, 2013, could have suppressed the number of infections to 56 or fewer, averting at least 127 infections,” Gonsalves and Crawford wrote. “[W]hereas an intervention on April 1, 2011, could have reduced the number of infections to ten or fewer, averting at least 173 infections.”
Those findings are based on computer modeling and data from the US Centers for Disease Control and Prevention. The investigators created an interactive model of the HIV outbreak in Scott County that allows users to examine scenarios where response to the HIV outbreak occurred at different points on the timeline. An option to show actual response dates indicates that the peak of HIV incidence had passed before an emergency was declared.
However, there were plenty of early warning signs, the researchers note. Available data suggested injection drug use was increasing as far back as 2004. In 2008, local health officials called for needle exchange programs in response to increased drug use, but the call fell on deaf ears. In 2010 and 2011, the state suffered an outbreak of hepatitis C infections. Again, the incident was not enough to sway state policymakers. In 2013, southeastern Indiana’s only HIV testing facility closed, making regular testing much more difficult for residents of Scott County.
After the HIV epidemic began a national story, then-Governor Mike Pence signed legislation allowing counties to set up needle exchange programs if they could demonstrate that a public health emergency existed. However, at the same time he signed the bill to allow needle exchange programs, he signed a second bill that stiffened penalties for possession of a needle with intent to inject drugs. Thus, on the same day it became easier to get clean needles, it also became riskier—those caught attempting to use a needle to inject drugs could now be charged with a felony and face up to 2.5 years in prison.
The study authors argue that states and regions with increasing rates of injection drug use ought to ensure they have sufficient monitoring and treatment programs in place to detect outbreaks like the one in Scott County.
“Future HIV outbreaks could be minimized if HIV testing and treatment are available in places vulnerable to the transmission of bloodborne infections among PWID,” Gonsalves and Crawford wrote. “Syringe-exchange programs and use of opioid-agonist therapy are crucial HIV prevention tools that could offer the chance to prevent new outbreaks among PWID.”
The study, “Dynamics of the HIV outbreak and response in Scott County, IN, USA, 2011—15: a modelling study” was published in The Lancet HIV.