INDIANAPOLIS - Indiana Gov. Mike Pence overrode state law and his own antidrug policies Thursday to authorize a short-term needle-exchange program designed to help contain HIV infections in a rural county where more than six dozen cases have been reported, all of them tied to intravenous drug use.

Pence issued an executive order declaring a public health emergency in Scott County, about 30 miles north of Louisville, Ky. The county, which typically sees about five HIV cases each year, has seen 79 new infections since December, health officials said.

All of those infected either live in Scott County or have ties to the county, and all of the infections have been linked to needle sharing among drug users. Most of the infections involve people who injected a liquefied form of the prescription painkiller Opana. Methamphetamine and heroin account for the remaining cases, health officials said.

Pence, a Republican, said officials from the Centers for Disease Control and Prevention who arrived in the county Monday said it would be "medically appropriate" to authorize some type of needle-exchange program to help stem the infections.

Such programs are illegal in Indiana, and Pence has opposed needle exchanges as part of drug-control efforts. But his order allows Scott County officials to request state approval for a limited, short-term program.

Needle exchanges are not allowed in Pennsylvania, either. In 1992, then-Mayor Ed Rendell declared a health emergency in the city, allowing Prevention Point Philadelphia to operate a syringe exchange, which has been credited with a substantial role in the decline of HIV/AIDS in the city.

Needle exchanges have opened in recent years in several New Jersey cities, including Camden, as pilot programs approved by Gov. Christie.

In Indiana, Pence said that he was acting to halt the spread of the virus "despite my reservations" about providing clean needles to addicts.

Needle-exchange programs allow drug users to turn in used hypodermic needles in return for sterile ones. Pence's executive order will run for 30 days. He will then consider whether to extend it for another 30 days.