The number of U.S. residents who inject opioids has risen in recent years in tandem with the rate of new cases of hepatitis C virus (HCV), strongly suggesting the former factor is driving the latter. The warning signs are particularly concerning among young people.

Injection drug use is also associated with HIV transmission, although HCV transmits much more readily via this route.

Centers for Disease Control and Prevention (CDC) researchers analyzed data from reports to the agency of diagnoses of acute (new) cases of hep C. They also relied on the Substance Abuse and Mental Health Services Administration’s data on national admissions to substance use disorder treatment facilities.

The researchers looked at data from 2004 to 2014, a period during which about 13,000 people were diagnosed with acute hep C. During this time, the annual rate of acute hep C diagnoses increased from 3 cases per 1 million people to 7 cases per 1 million.

Those between 18 and 29 years old saw the highest increases of key related measures during the study period: a respective fivefold, sevenfold and ninefold increase in the rates of acute hep C, admissions to substance use disorder facilities for heroin injection and admissions due to the injection of prescription opioids.

“The impact of this new wave of infections may not be felt immediately but could be devastating,” says study author Alice K. Asher, PhD, RN, a health scientist at the CDC’s Division of Viral Hepatitis. Asher promotes a harm-reduction-based response, advocating for the use of federal funds “under certain conditions” to support “certain services offered by syringe services programs.”