New hepatitis C infections are on the rise among teens and young adults in Pennsylvania, according to a Pennsylvania Department of Health (PDH) statement reported by Family Practice News.

According to laboratory data from 2003 to 2010, the incidence of confirmed or probable cases of hepatitis C nearly doubled among people ages 15 to 34, rising from 1,384 to 2,393, or from 43 to 72 cases per 100,000 people. This stands in contrast to a significant drop in new cases among other age groups, resulting in an overall decline in hep C incidence from 185 to 142 per 100,000 people.

According to the report, the increased incidence among adolescents and young adults is most likely related to “high-risk behaviors, such as intravenous drug use and unprotected sex between men—and, to a lesser degree, unprotected heterosexual sex.”

Reports from other areas, such as Massachusetts, have yielded similar results.

“We know high-risk behaviors are common in this age group,” said Sameh Boktor of the PDH. “We need to work more on characterizing risk factors, and we need to work more on developing effective prevention strategies in this very productive age group.”

These high-risk behaviors are on the rise in rural areas, Boktor said, with the incidence of hepatitis C in this younger population rising more sharply in rural districts than in urban areas—though this last bit of data isn’t definitive because the study covered relatively low populations of rural counties.

Boktor added that the PDH data actually underreports new cases, as not everyone with hepatitis C gets tested and not all test results are received by the health department.