Hepatitis C reinfection rates up in direct-acting antiviral era

There is an increased rate of hepatitis C virus (HCV) reinfection among people who inject drugs (PWIDs) after the scale-up of direct-acting antivirals (DAAs), reports a recent Scotland study.

“We estimate that less than half of reinfections have been detected in the DAA era because of inadequate levels of retesting beyond the first year following successful treatment,” the researchers said. “Sustained efforts that involve high coverage of harm reduction measures and high uptake of annual testing are required to ensure prompt diagnosis and treatment of those reinfected if the goals of elimination are to be met.”

By linking national clinical and laboratory HCV data, a total of 5,592 PWIDs were included in the present retrospective study. All had commenced HCV treatment between 2000 and 2018, and had subsequently achieved sustained virological response. Reinfection was defined as a positive antigen or RNA test.

A total of 5,686 SVR episodes were included in the analysis, of which 73 percent (n=4,126) had undergone at least one subsequent HCV RNA or antigen test. Overall, 361 reinfections were diagnosed until the end of 2019, yielding a reinfection rate of 3.9 per 100 person-years. Ninety-six percent of reinfected patients had two consecutive positive tests.

Rate of reinfection increased from 1.5 per 100 person-years in 2000–2009, before the DAA era, to 8.8 per 100 person-years in 2017–2018, during the DAA era. Reinfection was highest among those treated in prison (14.3 per 100 person-years) and in community settings (9.5 per 100 person-years).

Of note, among those who were treated during the DAA era (2015–2017), 68 percent were retested within the first year after SVR, but only 30 percent in the second year. The researchers estimated that around 200 reinfections remained undetected.