Adult injection drug users aged 30 years or younger are both at the highest risk for acquiring hepatitis C and transmitting HCV, according to a presentation at the International Symposium on Hepatitis Care in Substance Users.
Kimberly Page, PhD, MPH, MS, from the University of New Mexico Health Sciences Center, presented results from the Acute UFO study, which took place from 2003 to 2017 in San Francisco. According to Page, HCV incidence has been increasing among young injection drug users in general, and has increased in both urban and especially non-urban areas.
To assess the association between injecting user’s partner age and risk for HCV in injecting partnerships, the researchers prospectively gathered demographic, HCV risk behavior and injecting partnership data from 391 people who inject drugs.
All participants were negative for HCV according to anti-HCV and HCV RNA testing and reported one to three injecting partnerships (n = 909). Median age of participants was 24 years (range, 22-27 years). During follow-up, 99 participants developed HCV for an overall incidence rate of 27.8 per 100 person-years (95% CI, 22.9-33.9).
Sixty-seven participants reported that all their partners in the last 3 years were aged 30 years or older, 145 reported a mix of partner ages, and 179 reported that all their partners were younger than 30 years. While 60 participants reported that all their partners were HCV-negative, 150 reported that at least one partner was HCV-positive and 181 reported they were unaware of the HCV status of at least one partner.
From 2006 to 2017, the participants’ HCV incidence rate was highest among those with partners all younger than 30 years (34.5 per 100 person-years; 95% CI, 26-45.8), followed by those with mixed-age partners (27.1 per 100 person-years; 95% CI, 19.9-37) and those with partners all aged 30 years or older (15.9 per 100 person-years; 95% CI, 8.8-28.7).
In a multivariable model, the researchers observed the lowest incidence in participants whose partners were all aged 30 years or older and had at least one known partner with HCV (P = .06).
In her conclusion, Page advised that the protective factors at work among the relationships including older partners requires further exploration. Additionally, disclosure of HCV status within partnerships has potential to increase preventive behaviors and potentially reduce HCV incidence.
By Talitha Bennett