Health officials in Illinois have linked an increase in the number of hepatitis C virus (HCV) cases to growing injection drug use across the state, The Chicago Tribune reports.

According to the Illinois Department of Public Health d, the total number of reported hepatitis C cases increased 43 percent between 2006 and 2017, reaching nearly 9,840 cases in the past year. Many of the cases among individuals younger than 35 have been linked to injection drug use. 

“The rise in hepatitis C cases corresponds with the opioid epidemic in Illinois,” the department said in a press release. Residents are now being urged to get tested for hepatitis C, hepatitis B virus (HBV) and hepatitis A virus (HAV) and to get vaccinated against HAV and HBV (there is no vaccine for HCV).

Nationally, new cases of hepatitis C are also on the rise, largely among people who inject drugs. Recently, the Centers for Disease Control and Prevention reported that new HCV cases have nearly quadrupled in the United States between 2006 and 2016.

Meanwhile, health officials estimate that half of people with hepatitis C do not know that they have the virus. Though there is an increase in recent infections among young people, baby boomers (those born between 1945 and 1965) are still the most likely to be affected by the virus.