Low rate of hepatitis Delta virus co-infection in first-time blood donors diagnosed with chronic hepatitis B virus infection in the Netherlands.

BACKGROUND

Hepatitis Delta virus (HDV) requires co-infection with hepatitis B virus (HBV) and increases the risk of hepatitis-related morbidity and mortality compared to HBV mono-infection. HBV/HDV co-infected patients will likely benefit from new HDV antiviral drugs, but reliable estimates of co-infection rates are lacking due to limited HDV testing of HBV-infected patients.

STUDY DESIGN AND

METHODS

First-time blood and bone tissue donors in the Netherlands (2006-2023) with a newly diagnosed chronic HBV infection were retrospectively tested for HDV antibodies, and for HDV RNA if HDV antibodies were detected. HBV genotyping using phylogenetic analysis was performed to determine the most likely origin of HBV infection.

RESULTS

HBV-DNA was detected in 254/758.081 (0.034%) first-time donors in the Netherlands. HBsAg-positive first-time donors had a median age of 43 years (IQR: 33-52), were predominantly male (67%), mostly first- or second-generation migrants (76%) and HBV (sub)genotype strongly correlated with the country of birth. HDV testing was performed for 200 first-time donors with chronic (HBsAg-positive) HBV infection: 5 donors (2.5%) had HDV antibodies, and 1 donor (0.5%) also had detectable HDV RNA. None of the 17 donors with occult (HBsAg-negative) HBV infection had experienced HDV infection.

DISCUSSION: Chronic HBV/HDV co-infection in first-time donors in the Netherlands is extremely rare, affecting 0.00013% of all first-time donors, and only 0.5% of HBsAg-positive first-time donors consisting predominantly of migrants from high(er) HDV-endemic countries. Despite low HBV/HDV co-infection rates, a one-time HDV reflex testing strategy for HBsAg-positive patients remains essential to identify patients and to initiate antiviral treatment if needed to reduce the risk of serious liver disease.