A majority of people who inject drugs (PWID) in several U.S. cities have antibodies that indicate current or past infection with hepatitis C virus (HCV), according to a study report published in the Journal of Infectious Diseases.

The study shows that HCV prevalence among younger drug injectors may be catching up to the high rates traditionally seen in older people, likely as a result of the ongoing opioid epidemic. The findings underscore the need for stepped-up syringe services and other harm reduction efforts.

HCV is readily transmitted through shared syringes and other injection equipment, and people who use drugs have high rates of HCV incidence (new infections) and prevalence (total infections). Traditionally, baby boomers have had the highest burden of hepatitis C in the United States, but this could be shifting.

Winston Abara, MD, PhD, of the Centers for Disease Control and Prevention’s Division of Viral Hepatitis, and colleagues analyzed demographic characteristics and injection behaviors among participants in the National HIV Behavioral Surveillance program in eight cities: Chicago, Dallas, Denver, Los Angeles, New Orleans, New York, Seattle and the New York City region.

Of the 4,092 drug injectors surveyed, 55.2% tested positive for HCV antibodies. Broken down by age, the prevalence was 42.1% among people age 35 or under compared with 62.2% among those over 35. Across all ages, African Americans had a higher prevalence (58.6%), as did those with a high school diploma or GED or less education.

Additional factors associated with a higher likelihood of having hepatitis C included sharing injection equipment—especially receptive syringe sharing, or using a syringe after someone else—and injecting more often. People who injected speedball (a mixture of heroin and cocaine), which usually involves more frequent injection, had the highest prevalence, at 72.0%.

“Young PWID usually start injecting within sexual or social networks that can foster needle and syringe sharing behaviors,” the study authors wrote. “New injectors have little hepatitis C risk knowledge and may buy, prepare, divide and inject drugs in group settings where needle, syringe and injection equipment sharing are common.”

The authors further noted that many PWID are not aware of the risk of HCV transmission through sharing other injection equipment like cookers, filter or water or perceive the risk to be very low. In the younger group, having an arrest history was also a risk factor, perhaps because HCV risk behaviors such as needle sharing for drug use, tattoos and piercings is common in correctional settings. Arrests can also deter use of syringe services, they said.

“Educating young PWID on hepatitis C risk is especially important because the greatest risk of HCV infection is during the first few years after initiating injection, and many report hepatitis C risk behaviors and little knowledge of safer injection practices,” the researchers wrote.

With regard to hepatitis C care, 87.2% of those who were HCV positive reported that they had previously been tested before the survey, most often at public health clinics or community health centers or in correctional facilities. Among those who were tested and knew their status, only 19.2% had been treated.

Studies have shown that current and former drug users treated with direct-acting antivirals have high treatment completion and cure rates, and mathematical models suggest that scaling up treatment could greatly reduce hepatitis C prevalence and incidence.

“Given the current opioid crisis, it is likely that HCV infection attributable to injection drug use will continue to increase, particularly among young PWID,” the authors concluded. “Scaling up direct-acting antiviral treatment, syringe service programs and medication-assisted therapy is critical to mitigating transmission risk and infection burden.”

Click here to read the study abstract.