A needle exchange program helped bring the Indiana HIV outbreak under control, but two years of delay made the situation much worse than it needed to be. Diego Cervo/Shutterstock

Public health researchers have been studying hundreds of HIV infections in a rural Indiana county intensively to learn what went wrong, and how we can avoid similar cases in future. Political commentators have blamed Vice President Mike Pence, in his former role as Governor of Indiana, for letting it happen, and new research indicates Pence could have prevented most of the infections.

Scott County, Indiana, seldom makes news, with a population of just 24,000 and no famous landmarks. Recently, however, Scott has been noticed for very unfortunate reasons.

Scott has been hit particularly hard by the opioid/opiate crisis, with Indiana's proportionally highest number of premature deaths. Moreover, 215 people in Scott contracted HIV in 2011-2015, an astonishing number for such a small county long after the virus' late-80s peak.

Dr Gregg Gonsalves of Yale University has published a study in The Lancet HIV investigating the timings of infections and the likely effects of alternative responses.

"We used publicly available data on the outbreak to recreate it in a computer simulation," Gonsalves said in a statement. "Once we had recreated the events in Scott County, we could examine what would have happened if a response to the threat had been initiated earlier."

Indiana had ample warning. The HIV outbreak was preceded by even more cases of hepatitis C, which caused local public health experts to plead for action. For Scott County, both hep C and HIV were primarily spread through the sharing of needles during opiate injections, rather than sexual contact, so a needle exchange program was the centerpiece of their recommendations.

"Our findings suggest that with earlier action the actual number of infections recorded in Scott County – 215 – might have been brought down to fewer than 56, if the state had acted in 2013, or to fewer than 10 infections, if they had responded to the [hepatisi C] outbreak in 2010-2011. Instead they cut funding for the last HIV testing provider in the county," said co-author Dr Forrest Crawford.

These mistakes are very relevant for the 220 US counties considered at risk of similar outbreaks by the Centers for Disease Control and Prevention (CDC). An accompanying paper discusses how to prevent repetitions. Gonsalves claimed; “Unless we act, it's not a question of whether we'll see a repeat of what happened in Scott County, but when and where."

Only epidemiologists might be paying much attention, however, were it not for the individual most responsible. Mike Pence became Governor of Indiana in January 2013 and resisted needle exchanges for more than two years arguing, against overwhelming evidence, they encourage opiate use. Pence eventually declared a public health emergency in March 2015, opening an HIV testing clinic and temporarily allowing syringe exchanges. The program worked but Gonsalves and Crawford make clear the time for action was much earlier.