Low Prevalence of Occult Hepatitis B Infection Among Blood Donors in Beirut, Lebanon: Reconsider the Deferral Strategy of Anti-HBc Positive Blood Donors

Hepatitis B virus (HBV) infection remains one of the major infectious threats to human health. Since the implementation of highly sensitive HBV nucleic acid testing, occult HBV infection (OBI) has been detected. Occult HBV infection is characterized by a positive HBV DNA test with undetectable HBsAg (Hepatits B surface antigen). The prevalence of OBI varies significantly between geographic areas, genotypes, and population depending on the sensitivity of the detection assays used.
This project aimed at determining the prevalence of OBI in blood donors from a major blood donor center in Beirut, Lebanon through testing for 4 HBV markers (HBsAg, anti-HBs, anti-HBc and HBV DNA).
A total of 7437 blood donors were first tested for anti-HBc marker between August 2013 and March 2015; samples positive for anti-HBc were tested for other serological markers and HBV genome. DNA was extracted from 500 μL of plasma and tested for HBV DNA using Artus HBV TM PCR Kit assay. All anti-HBc positive samples were tested by nested PCR, targeting the S gene.
This study revealed a 4.6% prevalence of anti-HBc positive blood donors (341/7437). Among anti-HBc positive blood donors, 21 were HBsAg positive (6.2%) and 75% were positive for anti-HBs. The occurrence of occult hepatitis B virus in healthy seropositive blood donors during a 20 month period was very low; only 1 Syrian blood donor (n = 1/341, 0.3%) was HBsAg negative, HBV DNA-positive with anti-HBs level > 1000 mIU/mL.
Our study indicates that HBV DNA is present in a small percentage of HBsAg negative, anti-HBc reactive units. Lebanon has developed its own blood screening strategy, which is to screen for anti-HBc in addition to HBsAg. This is based on HBV prevalence and cost-effectiveness of testing methods. The disadvantage of not implementing nucleic acid testing (NAT) is missing rare blood units from donors in the window period.