An HIV outbreak in southeastern Indiana related to intravenous prescription drug abuse has reached 106 confirmed and preliminary cases, state public health officials said on Friday.

As of Thursday there were 95 confirmed HIV cases and 11 preliminary cases from the outbreak in rural Scott County, some 30 miles north of Louisville, Kentucky, a state joint information center said.

Scott County has been the center of the outbreak, the biggest in the state's history.

A short-term state-authorized needle exchange program began on Saturday in Scott County to combat the outbreak. The program authorized by Governor Mike Pence expires on April 25, but may be extended if necessary.

Needle exchange programs provide drug users with sterile needles to try to prevent infections from spreading through the sharing of contaminated needles.