Hepatitis B virus in transfusion medicine: still a problem?

Area of Science:

• Hepatology
• Virology
• Immunology

Background:

• Hepatitis B virus (HBV) has co-evolved with humans for millennia, diversifying into nine genotypes (A-I) with distinct epidemiological and clinical implications.
• Genotypes E and C are associated with increased infectivity, chronicity, and cancer risk.
• While HBsAg blood screening has reduced transfusion transmission, residual risk necessitates highly sensitive nucleic acid testing (NAT).

Purpose of the Study:

• To review recent findings on host immune system limitations, immunodeficiency impacts, and viral persistence mechanisms in Hepatitis B.
• To highlight the necessity of dual screening for both HBsAg and viral particles for efficient HBV detection.
• To discuss viral variants, false-negative screening results, and implications for asymptomatic carriers and transfusion-transmitted infections.

Main Methods:

• Review of recent scientific literature on HBV infection, host immune response, and viral persistence.
• Analysis of HBV genotypes, their clinical significance, and screening assay limitations.
• Examination of mechanisms of viral escape, variant selection, and implications for blood safety.

Main Results:

• HBV utilizes host immune system limitations and generates variants to persist at low, unrecognized levels.
• Excess HBsAg and both infectious and defective viral particles are produced during replication.
• Current screening assays may miss variants, leading to false negatives, and dual screening is recommended.
• Asymptomatic carriers face long-term risks, and occult HBV infection (OBI) transmission via transfusion is a concern.

Conclusions:

• Understanding HBV persistence mechanisms and immune evasion is critical for managing chronic infection.
• Comprehensive screening strategies, including NAT and dual assays, are essential to minimize transfusion transmission risks.
• Further research is needed to elucidate long-term complications in asymptomatic carriers and refine transfusion safety protocols for OBI.