Occult HBV Infection in Nigeria

Area of Science:

• Virology
• Transfusion Medicine
• Public Health

Background:

• Occult hepatitis B virus infection (OBI) is defined by the presence of HBV DNA without detectable Hepatitis B surface antigen (HBsAg).
• OBI represents a potential risk in blood transfusion due to its undetectability by standard HBsAg screening.
• Previous studies on OBI prevalence in Nigeria are limited, necessitating local data for transfusion safety protocols.

Purpose of the Study:

• To determine the prevalence of OBI among HBsAg-negative blood donors in Ilorin, Nigeria.
• To evaluate the efficacy of HBsAg testing alone in diagnosing HBV infection in this population.
• To assess the risk of post-transfusion HBV infection in the study region.

Main Methods:

• A purposive sampling of 206 blood units from HBsAg-negative donors was conducted.
• Plasma samples were tested for HBsAg using ELISA and for HBV DNA using semi-nested Polymerase Chain Reaction (PCR).
• Genotyping of HBV DNA was performed using specific primers for genotype A and non-A strains.

Main Results:

• A total of 8.7% of donors were found to have OBI (HBV DNA positive).
• Retesting confirmed 3.9% of initially HBsAg-negative samples were positive by ELISA.
• HBV genotype A was predominant (83.3%) among OBI cases, with a higher prevalence in male donors.

Conclusions:

• The 8.7% OBI prevalence highlights a substantial risk of transfusion-transmitted HBV in Ilorin, Nigeria.
• HBsAg screening alone is insufficient for detecting OBI, underscoring the need for more sensitive methods.
• Implementing Nucleic Acid Testing (NAT) for HBV DNA detection in routine blood screening is crucial for ensuring transfusion safety in Nigeria.