Prevalence of occult Hepatitis B infection among blood donors attending a blood bank center in Beirut, Lebanon

Abstract

Background: Hepatitis B virus (HBV) infection remains one of the major threats to human health; it is estimated that this virus infects 400 million of the worlds population and is considered as one of the most common transfusion-transmitted viral infections. Since the implementation of highly sensitive HBV nucleic acid testing, occult HBV infection (OBI) has been detected. OBI is characterized by a positive HBV DNA test with undetectable HBsAg. The prevalence of occult HBV varies significantly between geographic areas and population depending on the sensitivity of the detection assays used. Method: Using a cross-sectional study, this project aimed at determining the prevalence of occult HBV in blood donors in a major blood donor center in Beirut, Lebanon through screening for four HBV markers that include HBsAg, anti-HBs, and nucleic acid test along with anti-HBc. A total of 7437 blood donors were first tested for anti-HBc marker from August 2013 to March 2015; 341 samples positive for anti-HBc were tested for serological markers and nucleic acid. Result: This study revealed a 4.6% prevalence of anti-HBc positive blood donors. Among anti-HBc positive blood donors, 21 were HBsAg positive with a prevalence of 6.2% and 75% were positive for anti-HBs. The occurrence of occult Hepatitis B virus in healthy seropositive blood donors during a 20 months period was very low; only one Syrian blood donor (n=1/341, 0.3%) was HBsAg negative, HBV DNA-positive with anti-HBs level > 1000 mIU/mL. Conclusion: Our study has demonstrated that HBV DNA is present in a small percentage of HBsAg negative, anti-HBc reactive units. Introducing HBV NAT is more favorable in high endemic areas, where OBI prevalence is high, compared to those with low endemicity of HBV infection. Therefore, Lebanon has developed its own blood screening strategy, which is to screen for only anti-HBc serological marker. This is based on HBV prevalence and cost-effectiveness of testing methods. The disadvantage of not implementing NAT testing is the risk of transfusion blood unit from a donor in the window period.