By Lisa Rapaport

(Reuters Health) – A years-long HIV outbreak among intravenous (IV) drug users in Indiana might have been avoided if the state’s top medical and political leaders had acted sooner on early warnings that the virus was spreading, a recent study suggests.

From 2011 to 2014, Scott County, Indiana, was the site of a severe HIV outbreak among people who inject drugs, with a cluster of 215 infections ultimately attributed to the outbreak, researchers note in The Lancet HIV.

Undiagnosed HIV cases attributed to the outbreak peaked at 126 around January 10, 2015, roughly two months before then-governor Mike Pence declared a public health emergency and three months before the county established a temporary needle exchange program, the study authors write.

If state officials had stepped up HIV screening and treatment efforts in 2011, there would have been fewer than 10 infections total, the researchers estimate.

Even intervening in 2013 instead of waiting until 2015 might have limited the outbreak to no more than 56 HIV infections, the study team calculated.

“This is a very conservative approach – we didn’t add in specific effects for the impact of needle exchange and opioid (addiction medication), all of which would have further tamped down the epidemic,” said study co-author Gregg Gonsalves of the Yale School of Public Health in New Haven, Connecticut.

“So even with a modest set of interventions – testing and diagnosis – initiated in 2011 and 2013, the outbreak could have been largely avoided,” Gonsalves said by email. “With a comprehensive response, it might have been avoided altogether.”

Researchers used publicly available data on the outbreak, including dates of diagnosed cases and interventions in response to the public health crisis in a computer simulation designed to calculate how intervening at different times might impact the trajectory of the outbreak.

Previous research by the U.S. Centers for Disease Control and Prevention (CDC) established that the HIV outbreak in Scott County started in 2011 and spread throughout the community of people who use drugs in and around Austin, Indiana, the study authors note.

CDC investigators have also indicated that 220 other counties in the United States are at risk of HIV and hepatitis C outbreaks related to opioid injection use similar to what was seen in southeastern Indiana, they write.

Although the study specifically evaluates the Scott County outbreak, new clusters of cases of HIV among people who use drugs have already been reported in Ohio, Kentucky, West Virginia and Massachusetts, the study authors add.

HIV is transmitted when IV drug users share injecting equipment. Tiny amounts of blood are drawn up into syringes as people inject heroin or other drugs and this blood and any blood-borne infections like HIV or hepatitis C can get transferred to anyone who shares their needles.

Needle exchange breaks this chain of infection by providing clean needles so drug users so don’t have to share injecting equipment.

The study results reinforce the importance of so-called syringe service programs like needle exchanges to prevent the spread of HIV, said Dr. John Brooks, senior medical advisor with the CDC’s Division of HIV/AIDS Prevention.

“It also reinforces the importance of recognizing potential outbreaks early and reacting to them quickly with proven, effective interventions like HIV and viral hepatitis testing and treatment – and linkage to medication assisted therapy for opioid use – to cut off further spread,” Brooks, who wasn’t involved in the study, said by email.

In response to the Indiana outbreak, the CDC conducted a nationwide assessment to identify places in the country that might be vulnerable to HIV and hepatitis C outbreaks among people who inject drugs, and several communities across the country set up syringe programs in response, Brooks added.

Beyond these efforts, communities can also do more to de-stigmatize treatment for opioid addiction and HIV, said Steffanie Strathdee, a researcher at the University of California, San Diego who wasn’t involved in the study.

“The take home message is that ultra-conservative policies (and politicians) that criminalize drug users and operate under a ‘war on drugs’ mentality not only don’t work, they perpetuate HIV transmission and other harms associated with the opioid crisis,” Strathdee said by email. “The best way people can support drug users is to stop stigmatizing and jailing them.”

SOURCE: The Lancet HIV, online September 13, 2018.