Hepatitis B and C co-infection linked to worse liver fibrosis than hepatitis B alone

People with both hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection may experience more rapid and severe liver disease progression than those with hepatitis B alone, though HBV/HCV co-infection did not appear to worsen hepatitis C progression, according to a French study presented at the European Association for the Study of the Liver (EASL) 50th International Liver Congress in April in Vienna, Austria.

Due to overlapping transmission routes, many people are co-infected with both HBV and HCV. Previous research has shown that HBV and HCV appear to compete with each other in the body, with one virus typically becoming dominant. Studies indicate that co-infection with both viruses may lead to more severe liver disease, but research has been limited for non-Asian patients (Asia and Africa have the highest prevalence of hepatitis B worldwide).

Stanislas Pol from Université René Descartes in Paris, France, and colleagues analysed characteristics and outcomes among people with HBV and HCV co-infection in the ANRS CO22 HEPATHER cohort, comparing them to participants with either hepatitis B or C mono-infection.

HEPATHER is a large cohort of people with hepatitis B and/or C, followed at more than 30 centres in France, with centralised collection of biological specimens. It aims to enrol 10,000 people with hepatitis B and 15,000 people with hepatitis C.

This analysis looked at 14,698 participants enrolled as of November 2014. Within this group, 1099 had serological evidence of having been infected with both HBV and HCV, while 9098 had HCV alone and 4501 had HBV alone. Of these, 92 people with active HBV and HCV co-infection were matched by age, sex and duration of infection with four people who had HBV alone and four with HCV alone.

Rates of hepatitis delta (HDV) infection were similar for hepatitis B patients with and without HCV, and HCV genotype distribution was the same for hepatitis C patients with and without HBV.

People with HBV and HCV co-infection and those with HCV alone had similar rates of advanced fibrosis or cirrhosis (Metavir stage F3-F4), but both were significantly higher than the rate for people with HBV alone (42% and 40% vs 15%, respectively).

People with co-infection were significantly more likely to have low-level HBV DNA (<50 IU/ml) than those with HBV alone (87% vs 62%), supporting the idea that HCV suppresses HBV. However, people with co-infection and those with HCV alone were about equally likely to have high HCV RNA levels (>6.1 log₁₀) at enrolment (43% vs 49%).

People with co-infection were less likely to have received hepatitis C treatment than people with HCV alone (51% vs 67%) and less likely to be on ongoing hepatitis B treatment than those with HBV alone (29% vs 38%).

"HBV coinfection was not associated with the severity of HCV-associated chronic hepatitis," the researchers summarised. "In contrast, HCV coinfection harmfully impacted on fibrosis [in people with HBV]." Interestingly, they added, "HCV coinfection may reduce HBV replication in B/C coinfected patients."

Thus, they concluded, "HCV treatment initiation must be prioritized in patients with an HBV/HCV coinfection, regardless of the severity of liver disease."